View source for Barred owl

{{Short description|Species of owl}}
{{Distinguish|Barn owl}}
{{Speciesbox
| image = Strix-varia-005.jpg
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2016 |title=''Strix varia'' |volume=2016 |article-number=e.T22689094A93217844 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22689094A93217844.en |access-date=12 November 2021}}</ref>
| status2 = CITES_A2
| status2_system = CITES
| status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref>
| genus = Strix
| species = varia
| authority = [[Benjamin Smith Barton|Barton]], 1799
| synonyms =''Syrnium varium''
| subdivision_ranks = Subspecies
| subdivision =
*''S. v. georgica''
*''S. v. helveola''
*''S. v. varia''
| range_map = Strix varia map.svg
}}

The '''barred owl''' ('''''Strix varia'''''), also known as the '''northern barred owl''', '''striped owl''' or, more informally, '''hoot owl''' or '''eight-hooter owl''', is a North American large species of [[owl]]. A member of the [[true owl]] family, Strigidae, they belong to the genus ''[[Strix (genus)|Strix]]'', which is also the origin of the family's name under [[Linnaean taxonomy]].<ref name= Sclater>{{cite journal|doi=10.1111/j.1474-919X.1879.tb07718.x |title=Remarks on the Nomenclature of the British Owls, and on the Arrangement of the Order Striges |date=2008 |last1=Sclater. |first1=P. L. |journal=Ibis |volume=21 |issue=3 |pages=346–352 }}</ref><ref name= Konig>{{Cite book|title=Owls: A Guide to the Owls of the World|last1=Konig|first1=Claus|last2=Weick|first2=Friedhelm|last3=Becking|first3=Jan-Hendrick|publisher=Yale University Press|year=1999|pages=327–328}}</ref> Barred owls are largely native to eastern [[North America]], but have expanded their range to the west coast of North America where they are considered invasive.<ref name="iucn status 12 November 2021" /><ref name= Evers>Evers, L. (2014). ''Beyond anyone's control''. Northwest Science, 88(1), 65–67.</ref><ref name= Kelly>Kelly, E. G. (2001). [https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/xg94hs869 ''The range expansion of the northern barred owl: an evaluation of the impact on spotted owls'']. Thesis, Oregon State University.</ref> [[Old-growth forest|Mature forests]] are their preferred habitat, but they can also acclimatise to various gradients of open [[woodland]]s.<ref name= BNA>Mazur, K. M. & James, P.C. (2020). "Barred Owl (''Strix varia'')", version 1.0. In ''Birds of the World'' (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> Their diet consists mainly of small [[mammal]]s, but this species is an [[Generalist and specialist species|opportunistic predator]] and is known to prey upon other small [[vertebrate]]s such as [[bird]]s, [[reptile]]s, and [[amphibian]]s, as well as a variety of [[invertebrate]]s.<ref name= Audubon>{{Cite news|url=http://www.audubon.org/field-guide/bird/barred-owl|title=Barred Owl|date=2014-11-13|work=Audubon|access-date=2017-09-01}}</ref>

Barred owls are brown to gray overall, with dark striping on the underside. Barred owls have typical nesting habits for a true owl, tending to raise a relatively small brood often in a [[tree hollow]] or [[Snag (ecology)|snag]] (but sometimes also in other nesting sites) in forested areas.<ref name= Voous>{{cite book | last =Voous | first = Karel H. | author-link = Karel H. Voous |author2 = Cameron, Ad (illustrator) |title = ''Owls of the Northern Hemisphere''| year = 1988 | publisher = London, Collins | isbn =978-0-00-219493-8|pages =225–230}}</ref> As a result of the barred owl's westward expansion, the species has begun to encroach on the range of the related and threatened [[spotted owl]] (''S. occidentalis''). Evidence shows the assorted threats posed by the invading barred species are only increasing. In response, biologists have recommended culling operations to mitigate the negative effect of the barred on the spotted owl species.<ref name= Buchanan>{{cite journal|title=A synopsis of suggested approaches to address potential competitive interactions between Barred Owls (''Strix varia'') and Spotted Owls (''S. occidentalis'')|date=2007 |doi=10.1007/s10530-006-9068-7 |last1=Buchanan |first1=Joseph B. |last2=Gutiérrez |first2=R. J. |last3=Anthony |first3=Robert G. |last4=Cullinan |first4=Tim |last5=Diller |first5=Lowell V. |last6=Forsman |first6=Eric D. |last7=Franklin |first7=Alan B. |journal=Biological Invasions |volume=9 |issue=6 |pages=679–691 |bibcode=2007BiInv...9..679B |s2cid=20935420 }}</ref><ref name= Livezey>{{cite journal|author=Livezey, K. B. |year=2010|title=Killing barred owls to help spotted owls I: a global perspective|journal= Northwestern Naturalist|volume=91|issue=2|pages= 107–133|doi=10.1898/NWN09-37.1 |jstor=40856470|s2cid=11691153 }}</ref>

== Basics ==
[[File:Fulvous Owl (Strix fulvescens) (5957075195).jpg|thumb|Although previously considered a subspecies of barred owl, the [[fulvous owl]] is now considered a distinct species]]

The barred owl was first described by [[Philadelphia]] naturalist [[Benjamin Smith Barton]] in 1799. The species was named due to the varied directions the dusky markings take on their underside.<ref>Barton, B. S. (1883). ''Barton's Fragments of the Natural History of Pennsylvania''. Willughby Society.</ref>

The barred owl is roughly intermediate in size between the larger Ural and the smaller tawny owl, but the structural features of its relatively short and decurved [[claw]]s more so resemble the tawny species as does their dietary and habitat ecology.<ref name= Voous /> The [[spotted owl]] has been hypothesized to be within a [[Species complex|superspecies]] with the barred owl.<ref>Mayr, E., & Short, L. L. (1970). ''Species taxa of North American birds: a contribution to comparative systematics''. Nuttall Ornithological Club.</ref> However, genetic testing reveals very early divergence (likely at or near their ancestor's entry to North America) between spotted and barred owls.<ref>{{cite journal|title=Northern spotted owl (''Strix occidentalis caurina'') genome: divergence with the barred owl (''Strix varia'') and characterization of light-associated genes|date=2017 |pmid=28992302 |pmc=5629816 |doi=10.1093/gbe/evx158 |last1=Hanna |first1=Zachary R. |last2=Henderson |first2=James B. |last3=Wall |first3=Jeffrey D. |last4=Emerling |first4=Christopher A. |last5=Fuchs |first5=Jérôme |last6=Runckel |first6=Charles |last7=Mindell |first7=David P. |last8=Bowie |first8=Rauri C. K. |last9=Derisi |first9=Joseph L. |last10=Dumbacher |first10=John P. |journal=Genome Biology and Evolution |volume=9 |issue=10 |pages=2522–2545 }}</ref> A fossil species once called ''Strix brea'' from the early Pleistocene in California does little to resolve the ancestry of modern species, given its ambiguous relation to any living ''Strix''. The fossil species was larger (more similar in size and slenderness to the spotted owl, albeit with a slightly smaller skull and geographically isolated from that species) and longer-legged than either the spotted and barred owls, and is now considered to be in a separate genus, ''[[Oraristrix]]''.<ref>{{cite journal|doi=10.3853/j.0067-1975.62.2010.1534|title=A new genus for the extinct late Pleistocene owl ''Strix brea'' Howard (Aves: Strigiformes) from Rancho La Brea, California|journal=Records of the Australian Museum|volume= 62|pages= 123–144|author1=Campbell Jr, K. E.|author2=Bochenski, Z. M. |year=2010|doi-access=free}}</ref><ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/condor/v035n02/p0066-p0069.pdf|author=Howard, H. |title=A New Species of Owl from the Pleistocene of Rancho la Brea, California |journal=The Condor |date=1933 |volume=35 |issue=2 |pages=66–69 |doi=10.2307/1363650|jstor=1363650 }}</ref> Pleistocene era fossils of probable barred owls are known from Florida, Tennessee and Ontario.<ref>{{cite journal|jstor=4085986| author1=Parmalee, P. W.| author2=Klippel, W. E. |year=1982|journal= The Auk|volume= 99|issue=2|pages= 365–368|title=Evidence of a Boreal Avifauna in Middle Tennessee during the Late Pleistocene}}</ref>

=== Subspecies ===
[[File:Barred Owl (Strix varia) (9732594639).jpg|thumb|left|Some [[subspecies]] such as ''S. v. georgica'' from Florida differ from northern barred owls by their darker brown streaks and, more noticeably, their bare toes]]
[[File:Barred Owl (25840348850).jpg|thumb|right|The Texas subspecies, ''S. v. heveola'', has mostly bare and relatively sizable toes and distinctly cinnamon-hued plumage]]

The subspecies of the barred owl vary mostly by region, with slight to moderate variation by coloring, size and extent of feathering on the toes. Although several have been described in the past, the barred owl may include only three subspecies, subsequent to the separation of the fulvous and cinereous forms.<ref name= Ridgway /><ref>Peters, J. L. (1940). ''Check-list of birds of the world. Vol. 4''. Cambridge: Harvard Univ. Press.</ref>

*''S. v. varia'' (Barton, 1799): The northern barred owl. This race lives throughout the [[Northeastern United States]] and the [[Upper Midwest]], ranging as far south as [[Oklahoma]], the [[Carolinas]] and northern [[Georgia (U.S. state)|Georgia]]. It is also considered to comprise all western "invader" birds found as far west as California and British Columbia.<ref name= Konig /><ref name= BNA /> However, genetic study of westerly birds show a substantial isolation, possibly up to the subspecific level, of the western and eastern populations of the northern owls, with an estimated divergence of around 7,000 years, perhaps indicating an unknown history of the species in remote forests of northern and central Canada (far west of what was considered their original distribution) that radiated more recently to comprise the western populations.<ref>{{cite journal|title=Genomic Variation and Recent Population Histories of Spotted (''Strix occidentalis'') and Barred (''Strix varia'') Owls|date=2021 |doi=10.1093/gbe/evab066 |last1=Fujito |first1=Naoko T. |last2=Hanna |first2=Zachary R. |last3=Levy-Sakin |first3=Michal |last4=Bowie |first4=Rauri C K. |last5=Kwok |first5=Pui-Yan |last6=Dumbacher |first6=John P. |last7=Wall |first7=Jeffrey D. |journal=Genome Biology and Evolution |volume=13 |issue=5 |pmid=33764456 |pmc=8120011 }}</ref> This race is generally the typical mid gray-brown variety of barred owl.<ref name= Konig /> However, a paler variation with very washed out markings and a more pure whitish base color is known (in eastern Canada such as Quebec), formerly considered a race ''S. v. albescens'', as well as darker and browner variation in northern Minnesota (formerly ''S. v. brunnescens'').<ref name= BNA /><ref>{{cite journal|author=Bishop, L. B. |year=1931|title=Three apparently undescribed owls|journal= Proceedings of the Biological Society of Washington|volume= 44|pages= 93–95}}</ref> This race is fairly large (described as the largest race on average with the probable separation of the cinereous owl). The [[Wing chord (biology)|wing chord]] and tail length may measure from {{convert|312|to|340|mm|in|abbr=on}} and {{convert|215|to|230|mm|in|abbr=on}} in males and {{convert|320|to|352|mm|in|abbr=on}} and {{convert|224|to|257|mm|in|abbr=on}} in females.<ref name= Konig /><ref name= Ridgway /> One nominate bird had a [[Tibiotarsus|tarsus]] length of {{convert|63.5|mm|in|abbr=on}} and the [[Culmen (beak)|culmen]] from the cere may measure {{convert|23.5|to|30|mm|in|abbr=on}}.
*''S. v. georgica'' ([[John Latham (ornithologist)|Latham]], 1801): The southern barred owl or, alternately, the Florida barred owl. This subspecies is found in southern [[North Carolina]] closer to the coast along to broadly through [[Georgia (U.S. state)|Georgia]] and all of [[Florida]].<ref name= BNA /><ref name= Ridgway /><ref>{{cite journal|doi=10.2307/4075950|jstor=4075950 |last1=Wetmore |first1=Alexander |title=The Florida Barred Owl in North Carolina |journal=The Auk |date=1930 |volume=47 |issue=2 |page=253 |doi-access=free }}</ref> This is the smallest of the three subspecies on average.<ref name= Konig /><ref name= BNA /> Known wing chord lengths can vary from {{convert|315|to|357|mm|in|abbr=on}}. Tail length is {{convert|205|to|231|mm|in|abbr=on}} and the bill from the cere is {{convert|23|to|28|mm|in|abbr=on}}.<ref name= Konig /><ref name= BNA /> Males in Florida were found to weigh from {{convert|681|to|800|g|lb|abbr=on}}, with averages in two samples of {{convert|718|and|744|g|lb|abbr=on}}, while two females weighed {{convert|850|and|875|g|lb|abbr=on}}, respectively. It therefore appears to show less pronounced [[sexual dimorphism]] than the northern barred owl race.<ref name= Weidensaul />
*''S. v. helveola'' ([[Outram Bangs|Bangs]], 1899): The Texas barred owl. Comprises most barred owls found in Texas.<ref name= Konig /> The distributional range is considered to range as far north as [[Lee County, Texas|Lee County]], east to [[Chambers County, Texas|Chambers County]], west to [[Kerr County, Texas|Kerr County]] and south to [[Nueces County, Texas|Nueces County]].<ref name= BNA /><ref name= Howell>Howell, S. N., & Webb, S. (1995). ''A guide to the birds of Mexico and northern Central America''. Oxford University Press.</ref><ref>Oberholser, H. C. (1974). ''The Bird Life of Texas''. University of Texas Press, Austin, TX, USA.</ref> In this race, the ground coloration tends to pale gingery-cream and the back and head tend to be a pale brown ranging into an almost cinnamon color.<ref name= BNA /> The toes can vary from rather bare to slightly bristled.<ref name= Konig /> This race is similar to other barred owls in size, perhaps averaging marginally smaller than those in the nominate race, but its bill and feet are larger on average than the preceding two races.<ref name= BNA /><ref name= Ridgway />

== Description ==
[[File:Barred Owl Closeup.jpg|thumb|left|A barred owl in [[Ontario]]|alt=Close-up, [[Ontario]]]]

The barred owl is considered somewhat subdued and drab in coloration compared to the sometimes rich coloring of other [[Sympatry|sympatric]] owls.<ref name= Hume>Hume, R. (1991). ''Owls of the world''. Running Press, Philadelphia.</ref> Overall, this owl is greyish-brown or brown. The brownish color extends from the head to the back. Barred owls are scalloped with white bars on the mantle and the back, bearing as well some whitish spotting on the [[Covert feather|wing coverts]].<ref name= Voous /><ref name= BNA /> The underside has a pale creamy gray-brown base color (ranging into dirty white in the palest individuals) overlaid about the throat and upper chest with horizontal, slightly crescent-shaped barring (hence its common name), while the belly is boldly streaked in a vertical pattern. The streaking is usually blackish, dusky brown, or sometimes rufescent- (reddish-) brown.<ref name= Konig /><ref name= Hume /> The head is fairly large (although not especially so for a species in ''Strix'') and rounded with no [[ear tuft]]s.<ref name= Mikkola>''Owls of the World: A Photographic Guide'' by Mikkola, H. Firefly Books (2012), {{ISBN|978-1-77085-136-8}}</ref><ref name= HBW>Holt, D.W., Berkley, R., Deppe, C., E. Rocha, P., Petersen, J.L., Rangel Salazar, J.L., Segars, K.P., Wood, K.L. & Marks, J.S. (2019). "Typical Owls". In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). ''Handbook of the Birds of the World Alive''. Lynx Edicions, Barcelona.</ref> The [[facial disc]] is pale grayish-brown with darker yet subtle [[Concentric objects|concentric lines]].<ref name= Voous /> The [[Beak|bill]] is pale straw-yellow (occasionally showing a mild greenish tint) while the cere (a bare structure at the base of the beak) is "horn-colored".<ref name= Voous /><ref name= Hume /> Its eyes are a dark brown color; the eyes may appear intensely black in the field and, although large, are fairly closely set.<ref>{{Cite web |title=Barred Owl Identification, All About Birds, Cornell Lab of Ornithology |url=https://www.allaboutbirds.org/guide/Barred_Owl/id |access-date=2023-12-14 |website=www.allaboutbirds.org |language=en}}</ref><ref name= Hume />

The barred owl has well-developed eye anatomy. As is typical of owls, their ocular anatomy is quite distinct from [[diurnal raptor]]s especially in terms of their [[photoreceptor cell]]s, as they have a very large number of [[rod cell]]s in their quite sensitive [[retina]].<ref name= Weidensaul /><ref name= Braekevelt>{{cite journal|title=Fine structure of the retinal photoreceptors of the barred owl (''Strix varia'')|date=1996 |pmid=8720450 |last1=Braekevelt |first1=C. R. |last2=Smith |first2=S. A. |last3=Smith |first3=B. J. |journal=Histology and Histopathology |volume=11 |issue=1 |pages=79–88 }}</ref> However, their [[pecten oculi]] is smaller relative to the size of their large [[Orbit (anatomy)|ocular globe]] (other large [[Great horned owl|owls]] are known to have similar pecten proportions).<ref name= Braekevelt /> The vision in limited or almost no light during a laboratory study of a barred owl was found to be similar to that of other owls, including the [[long-eared owl]] (''Asio otus'') and the [[Western barn owl|barn owl]] (''Tyto alba'').<ref>{{cite journal|doi=10.1086/281276|jstor=2457707 |title=Minimum Intensities of Illumination Under Which Owls Can Find Dead Prey by Sight |date=1945 |last1=Dice |first1=Lee R. |journal=The American Naturalist |volume=79 |issue=784 |pages=385–416 |s2cid=86535713 }}</ref> The tarsi and toes are feathered up to the dark gray, black-tipped talons. These feathers are more sparse and bristled in the southern races. On individuals with bare sections of their toes, the toes are yellowish-gray in color.<ref name= Voous /><ref name="Terres">{{cite book| last =Terres| first =J. K.| author-link =John Kenneth Terres| title =The Audubon Society Encyclopedia of North American Birds| publisher =Knopf| year =1980| location =New York, NY| page =[https://archive.org/details/audubonsocietyen00terr/page/665 665]| isbn =0-394-46651-9| url-access =registration| url =https://archive.org/details/audubonsocietyen00terr/page/665}}</ref><ref>{{cite journal|doi=10.2307/4077355|jstor=4077355 |last1=Kelso |first1=Leon |last2=Kelso |first2=Estelle H. |title=The Relation of Feathering of Feet of American Owls to Humidity of Environment and to Life Zones |journal=The Auk |date=1936 |volume=53 |issue=1 |pages=51–56 |doi-access=free }}</ref> The flight feathers are barred with whitish buff and brown while the tail is brown or grayish-brown with 4–5 whitish bars.<ref name= Voous /> Young barred owls with their second set of [[down feather]]s are fluffy brownish-white, with indistinct darker barring on their head, back and mantle. They quickly become juveniles which resemble adults but have less distinct markings (especially about the head and neck), more buff coloring overall, often some remnant down, pinkish skin and a pale, blue-green cere. Also the tail at this age may have as many as seven bands (though sometimes have four like adults). Full adult plumage is obtained via [[Moulting|molt]] after about a year as well as adult bare part characteristics.<ref name= Voous /><ref name= BNA /><ref>{{cite journal|author=Shufeldt, R. W. |year=1911|title=Plumages of the Young of the Barred Owl|journal=The Wilson Bulletin|volume= 23|issue=2|pages=113–119|url=https://sora.unm.edu/sites/default/files/journals/wilson/v023n02/p0115-p0119.pdf}}</ref> A study of tail molt in [[Washington (state)|Washington]] showed that molt tends to occur relatively quickly, and that young individuals are difficult to age by state of molt alone.<ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/nabb_35-2_61-68.pdf|author1=Acker, J.|author2= Garcia, D. |year=2010|title=Notes on rectrix molt in Barred Owls (''Strix varia'')|journal=North American Bird Bander|volume= 35|issue=2|page=61}}</ref> Southern barred owls tend to be darker and slightly smaller than northerly ones.<ref>Karalus, K. E. & Eckert, E.W. (1974). ''The owls of North America (north of Mexico)''. Garden City, NY: Doubleday and Co.</ref> Rare captive and wild barred owls with [[albinism]] have been described and are pure white but tend to retain their brown eyes.<ref>{{cite journal|author=Dean, R. |year=1976|title=Albinism and melanism among North American Birds|journal= Bulletin of the Nuttall Ornithological Club|volume= 2|pages= 20–24}}</ref>

[[File:Barred-Owl 9146.jpg|thumb|A barred owl using its tail as an air dam and brake|right|alt=Landing on a fence post]]

The barred owl is a large species. The adult measures anywhere from {{convert|40|to|63|cm|in|abbr=on}} in length while the wingspan may range from {{convert|96|to|125|cm|in|abbr=on}}.<ref name="owlpages.com">[http://www.owlpages.com/owls.php?genus=Strix&species=varia Barred Owl (''Strix varia'') – Information, Pictures, Sounds]. The Owl Pages (2015-11-04). Retrieved on 2016-08-01.</ref><ref name= Ridgway>Ridgway, R., & Friedmann, H. (1914). ''The Birds of North and Middle America: A Descriptive Catalog of the Higher Groups, Genera, Species, and Subspecies of Birds Known to Occur in North America, from the Arctic Lands to the Isthmus of Panama, the West Indies and Other Islands of the Caribbean Sea, and the Galapagos Archipelago'' (Vol. 50). US Government Printing Office.</ref> The wing area (measured by square [[centimeter]] relative to the body mass) is quite intermediate among American owls, with the [[Bird flight|wing loading]] being lower than larger, but proportionately small-winged [[Horned owl|larger owls]] and even than some [[Screech owl|smaller owls]]. The barred has high wing-loading. Wing-loading is related to hunting technique, with higher wing-loading owls typically hunting from a perch, with only a brief flight necessary to obtain food, whilst lower wing-loading owls often hunt their prey from active flight. As is the case in most owls, the various wing feathers of barred owls are uncharacteristically soft and bear a [[comb]]-like shape, which in turn renders their flight functionally silent during their hunts.<ref>{{cite journal|doi=10.1093/icb/icy002|title=Barred Owl (''Strix varia'') Feather Pennulae|author1=Liu, L. G.|author2=Le Piane, K.|author3=Clark, C. J. |year=2018|journal= Integrative and Comparative Biology| volume =58 |pages=E364|doi-access=free}}</ref> Like most [[birds of prey]], the female is larger than the male barred owl, sometimes described as [[Sexual dimorphism|reverse sexual dimorphism]] (due to the fact that males average larger than females in most non-raptorial birds).<ref name= Konig />

Among standard measurements, the [[Wing chord (biology)|wing chord]] of grown males varies from {{convert|303|to|340|mm|in|abbr=on}}, with an average from three sources of {{convert|326.2|mm|in|abbr=on}}, the [[tail]] may measure from {{convert|182|to|250|mm|in|abbr=on}}, with an average of {{convert|219.6|mm|in|abbr=on}} and the [[Beak|culmen from the cere]] may measure from {{convert|22|to|27|mm|in|abbr=on}}, with an average of {{convert|24.3|mm|in|abbr=on}}. Meanwhile, for the female, the wing chord may range from {{convert|318|to|357|mm|in|abbr=on}}, averaging {{convert|335.8|mm|in|abbr=on}}, the tail from {{convert|204|to|257|mm|in|abbr=on}}, averaging {{convert|223.3|mm|in|abbr=on}} and the culmen from the cere {{convert|20|to|30.7|mm|in|abbr=on}}, averaging {{convert|25.1|mm|in|abbr=on}}.<ref name= Ridgway /><ref name="Earhart">{{cite journal |last1=Earhart |first1=Caroline M. |last2=Johnson |first2=Ned K. |date=1970 |title=Size Dimorphism and Food Habits of North American Owls |url=https://sora.unm.edu/sites/default/files/journals/condor/v072n03/p0251-p0264.pdf |journal=The Condor |volume=72 |issue=3 |pages=251–264 |doi=10.2307/1366002 |jstor=1366002}}</ref><ref name="Carpenter">{{cite journal |last1=Carpenter |first1=Thomas W. |date=1992 |title=Utility of Wing Length, Tail Length and Tail Barring in Determining the Sex of Barred Owls Collected in Michigan and Minnesota |journal=The Condor |volume=94 |issue=3 |pages=794–795 |doi=10.2307/1369270 |jstor=1369270}}</ref> Sexual dimorphism is particularly pronounced in barred owls by body mass as males within a population are sometimes a third lighter in weight.<ref name= Konig /><ref name= Ridgway /> In the nominate subspecies (''S. v. varia''), average weights for males have been reported as {{convert|621.9|g|lb|abbr=on}} (sample size 12), {{convert|632|g|lb|abbr=on}} (sample size 20) and {{convert|681|g|lb|abbr=on}} (sample size unknown) in three samples.<ref name= Ridgway /><ref name= Earhart /><ref name= Weidensaul>Weidensaul, S. (2015). ''Owls of North America and the Caribbean''. Houghton Mifflin Harcourt.</ref> The weight range for adult males is known to vary from {{convert|468|to|812|g|lb|abbr=on}}.<ref name= Ridgway /><ref name= Earhart /> The considerably larger female of the nominate subspecies has been reported to average {{convert|801|g|lb|abbr=on}} (sample size 24), {{convert|872.6|g|lb|abbr=on}} (sample size 14) and {{convert|909.5|g|lb|abbr=on}} (sample size unknown). Altogether, fully-grown female barred owls may weigh from {{convert|610|to|1150|g|lb|abbr=on}}.<ref name= Ridgway /><ref name= Earhart /><ref name= Weidensaul />

=== Vocalization ===
[[File:Barred Owl (Strix varia) (W1CDR0000351 BD27).ogg|thumb|left|Barred owl song, recorded in Florida, US]]

The barred owl is a powerful vocalist, with an array of calls that are considered "spectacular, loud and emphatic".<ref name= Bent>Bent, A. C. (1961). ''Life Histories of North American Birds of Prey (part 2), Orders Falconiformes and Stringiformes (Vol. 170)''. US Government Printing Office.</ref> Calls probably carry well over {{convert|0.8|km|mi|abbr=on}}.<ref>Bosakowski, T. (1987). "Census of Barred Owls and Spotted Owls". In ''Biology and Conservation of Northern Forest Owls'': Symposium Proceedings: February 3–7, 1987, Winnipeg, Manitoba (Vol. 142, p. 307). Fort Collins, Colo.: Rocky Mountain Forest and Range Experiment Station.</ref> Its usual call is a series of eight accented hoots ''ok-ok-ok-ok ok-ok-buhooh'', or the "typical two-phrase hoot" with a downward pitch at the end.<ref name= Konig /><ref name= Odom>Odom, K. (2009). [https://scholar.uwindsor.ca/cgi/viewcontent.cgi?referer=&httpsredir=1&article=1296&context=etd ''Vocalizations, vocal behaviour, and geographic variation in the calls, duets, and duetting behaviour of a nonpasserine, the Barred Owl (Strix varia)'']. M.S. Thesis, University of Windsor.</ref> The most common mnemonic device for remembering the call is "Who cooks for you, who cooks for you all."<ref name= Voous /> Due to its best known call, the barred owl is sometimes colloquially referred to as ''Old Eight-Hooter''.<ref>Haas, F. C. & Burrows, R. (2005). ''Birds of Pennsylvania''. Lone Pine.</ref> At 80% of study posts in [[Virginia]], barred owls responded to playback of this call.<ref name= Mcgarigal>{{cite journal|doi=10.2307/1367961|jstor=1367961 |last1=McGarigal |first1=Kevin |last2=Fraser |first2=James D. |title=Barred Owl Responses to Recorded Vocalizations |journal=The Condor |date=1985 |volume=87 |issue=4 |pages=552–553 }}</ref> A further call is the "ascending type" or the "[[legato]]" call, a series of variable notes ending in ''oo-aw'' or ''hoo-aah''.<ref name= BNA /><ref name= Odom /> At least two other variations on the legato/ascending call are known.<ref name= Odom /> 56% of studied owls in Virginia engaged in the ascending type call but 36% uttered only the closing notes.<ref name= Mcgarigal /> The isolated ''hoo-aah'', sometimes called the "inspection call", was the most common song type in north Florida and the most likely to be heard during daylight.<ref name= Odom2>{{cite journal|doi=10.1525/cond.2010.090163 |title=A Quantitative Description of the Vocalizations and Vocal Activity of the Barred Owl |date=2010 |last1=Odom |first1=Karan J. |last2=Mennill |first2=Daniel J. |journal=The Condor |volume=112 |issue=3 |pages=549–560 |s2cid=54987338 |url=https://scholar.uwindsor.ca/biologypub/1028 |url-access=subscription }}</ref> Several other calls, although some are not dissimilar variations on the main calls, are known.<ref name= Mcgarigal /><ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/auk/v012n04/p0362-p0367.pdf|author1=Brewster, W.|author2=Chapman, F. M. |year=1891|title=Notes on the birds of the lower Suwanee River|journal=The Auk|volume=8|issue=2|pages=125–138|doi=10.2307/4068066 |jstor=4068066 }}</ref><ref>Saunders, A. A. (1951). ''A guide to bird songs''. New York: Doubleday.</ref> Some of these vary into cackles, hoots, caws and gurgles, at times described as "sudden demonic laughter", "cat-like screams" and "prolonged outbursts of cackling" and seem to be, among ''Strix'' species, an idiosyncrasy endemic to the barred owl.<ref name= Voous /><ref name= Bent /><ref>{{cite journal|doi=10.2307/4078760|jstor=4078760 |last1=Taber |first1=Wendell |title=The Scream of the Northern Barred Owl |journal=The Auk |date=1940 |volume=57 |issue=2 |page=253 |doi-access=free }}</ref>

Another call type is the "mumble", a grumbling, slurred and subtle ''err-ERR-err'', also an up-and-down "twitter" call at a high pitch.<ref name= Odom /> When agitated, this species will make a buzzy, rasping hiss about three times in three seconds, repeating every 10–30 seconds, and will click its beak together forcefully.<ref name= Bent /> Females and juveniles beg with high scratching ''skreeechch'' notes.<ref name= Konig /> The voice of the two sexes is similar, but the female has a higher-pitched voice with longer terminal notes.<ref name= Odom2 /><ref>{{cite journal|url=https://sora.unm.edu/node/137289|author1=Bird, D. M.|author2=Bird, J.O. |year=1977|title=Apparent distraction display by a Barred Owl|journal=Canadian Field-Naturalist|volume=91|issue=2 |pages=176–177|doi=10.5962/p.345368 |doi-access=free}}</ref> Of calls, 87 to 94% are identifiable to sex per one study.<ref name= Odom /> While calls are most common at night, the birds do call during the day as well, especially when provoked by human playback or imitation.<ref>{{cite book|last=Alderfer|first=Jonathan|title=National Geographic: Complete Birds of North America |url=https://archive.org/details/nationalgeograph00jona|url-access=registration|year=2006|publisher=National Geographic Society|location=Washington D.C.|pages=330–331|isbn=978-1-4262-0135-6}}</ref> They are more responsive than any hawk in the east to playback of calls of their own species.<ref name= Mosher>{{cite journal|jstor=4513583|author1=Mosher, J. A.|author2=Fuller, M. R.|author3= Kopeny, M. |year=1990|title=Surveying Woodland Raptors by Broadcast of Conspecific Vocalizations |journal=Journal of Field Ornithology|pages=453–461|url=https://sora.unm.edu/sites/default/files/journals/jfo/v061n04/p0453-p0461.pdf}}</ref> The barred owl is noisy in most seasons but peak vocalization times for barred owls tend to be between late January (in Florida) and early April (in Canada).<ref name= Odom2 /><ref name= Dunstan>{{cite journal|author1=Dunstan, T. C.|author2=Sample, S. D. |year=1972|title=Biology of barred owls in Minnesota|journal=Loon|volume=44|issue=4|pages=111–115}}</ref><ref name= Taylor>Taylor, P. (1983). ''Wings along the Winnipeg: birds of the Pinawa-Lac du Bonnet region, Manitoba''. Winnipeg, MB: (Eco Series no. 2.) Manitoba Nat. Soc.</ref> Two seasonal peaks in vocalizations, one right before breeding and another after the young have dispersed, were detected in [[Connecticut]], with peak vocalizations on nights with extensive cloud cover.<ref>Yannielli, L. C. (1989). ''Preferred habitat of barred owls (''Strix varia'') in Litchfield County, Connecticut, with additional comments on distribution and abundance''. M.S. thesis, South. Conn. State Univ.</ref> Peak times for vocalizations are between 6:00{{nbsp}}pm and 6:00{{nbsp}}am, with the least frequent vocalizations around mid-afternoon.<ref name= Odom2 />

== Distribution and habitat ==
[[File:Barred-Owl 9052.jpg|thumb|Winter in [[Vermont]]]]

The barred owl is distributed throughout most of the [[eastern United States]], as well as much of [[southern Canada]].<ref name= Konig /> They are found as far northeast as much of [[Nova Scotia]] (western two-thirds), [[New Brunswick]] and [[Sept-Îles, Quebec|Sept-Îles]], in much of [[Quebec]], up to [[Lake Mistassini]], and [[Ontario]], up to [[Moosonee]].<ref name="iucn status 12 November 2021" /><ref name= Erskine>{{cite book|author=Erskine, A. J.|year=1992|title=Atlas of Breeding Birds of the Maritime Provinces|publisher=Nova Scotia Museum, Halifax, NS, Canada}}</ref><ref>Gagnon, C. & Bombardier, M. (1996). "Barred Owl." In ''The breeding birds of Quebec: atlas of the breeding birds of southern Québec''., edited by J. Gauthier and Y. Aubry, 598–601. Québec Region, Montréal: Assoc. québecoise des groupes d'ornithologues, Prov. of Quebec Soc. for the protection of birds, Can. Wildl. Serv., Environ. Canada.</ref><ref name= Eagles>Eagles, P. F., Cadman, M. D., & Helleiner, F. M. (1987). ''Atlas of the breeding birds of Ontario''. University of Waterloo Press.</ref><ref name= Peck>Peck, G. K., & James, R. D. (1993). [https://sora.unm.edu/sites/default/files/11-18%20OB%20Vol12%231%20Apr1994.pdf ''Breeding Birds of Ontario: Nidiology and Distribution''. Volume 1: Nonpasserines] (first Revision-part A: loons to ducks). Ontario Birds, 11, 18–22.</ref> The barred owl has been recorded as ended up as far north as central [[Labrador]], though the species is not yet confirmed to breed in the province.<ref>{{cite journal|doi=10.22621/cfn.v118i2.929 |title=First Record of a Barred Owl, ''Strix varia'', in Labrador |date=2004 |last1=Schmelzer |first1=Isabelle |last2=Phillips |first2=Frank |journal=The Canadian Field-Naturalist |volume=118 |issue=2 |page=273 |doi-access=free }}</ref> The barred owl ranges in every part of the [[eastern United States]] continuously from northernmost [[Maine]] down throughout [[New England]], the [[Mid-Atlantic (United States)|Mid-Atlantic states]], much of the [[Midwestern United States|Midwest]], the [[Southeast United States]] and all of [[Florida]].<ref name="iucn status 12 November 2021" /><ref name= Weidensaul /> They are found to as far west without substantial gaps to the limits of western [[Minnesota]], easternmost [[South Dakota]], the southeastern corner of [[Nebraska]], the eastern half roughly of [[Kansas]], most of [[Oklahoma]] and [[east Texas]] to as far west as [[Cisco, Texas|Cisco]] and [[Burnet, Texas|Burnet]].<ref name="iucn status 12 November 2021" /><ref>Janssen, R. B. (1987). ''Birds in Minnesota''. University of Minnesota Press, Minneapolis, MN, USA.</ref><ref>Peterson, R. A. (1995). ''The South Dakota Breeding Bird Atlas''. South Dakota Ornithologists' Union, Northern Prairie Wildlife Research Center, Jamestown, ND, USA.</ref><ref>[[Paul Johnsgard|Johnsgard, P. A.]] (1979). ''Birds of the Great Plains: Breeding Species and their Distribution''. University of Nebraska Press, Lincoln, NE, USA.</ref><ref name= Johnsgard>[[Paul Johnsgard|Johnsgard, P. A.]] (1988). ''North American owls: biology and natural history''. Smithsonian Institution.</ref> Arguably and discontinuously from Texas, the species may range into central and southern [[Mexico]] but these populations are now often considered a [[Cinereous owl|separate species]].<ref name="iucn status 12 November 2021" /><ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/jrr/v027n03/p00154-p00160.pdf|author=Holt, D. W. |year=1993|title=Presence and distribution of Mexican owls: a review|journal= J Raptor Res|volume= 27|issue=3|pages= 154–160}}</ref> These initial parts of the range in the eastern and central stretches would be considered as where the species is "native".<ref name= BNA /><ref name= Livezey2>{{cite journal|doi=10.1674/0003-0031-161.1.49 |title=Range Expansion of Barred Owls, Part I: Chronology and Distribution |date=2009 |last1=Livezey |first1=Kent B. |journal=The American Midland Naturalist |volume=161 |pages=49–56 |s2cid=86276981 }}</ref> A wandering barred owl was once seen flying over [[Lake Michigan]] {{convert|48|km|mi|abbr=on}} from the nearest land.<ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/wilson/v059n02/p0111-p0111.pdf|author=Blake, E. R. |year=1947|title=Barred owl thirty miles from land|journal= The Wilson Bulletin|volume= 59|issue=2|page= 111}}</ref>

=== Range expansions ===
[[File:Juvenile barred owl.jpg|thumb|A juvenile barred owl peers out in the verdant forests of [[Washington (state)|Washington]], where the species is an "invasive" recent invader]]

The remaining parts of the range are considered where the barred owl introduced itself in the last century or so. The historical lack of trees in the [[Great Plains]] presumably acted as a barrier to the range expansion, and recent increases in forests broke down this barrier.<ref name= Livezey2 /> Increases in forest distribution along the [[Missouri River]] and its tributaries provided barred owls with sufficient foraging habitat, protection from the weather, and concealment from avian predators. This allowed barred owls to move westward, initially solely along other [[Riparian zone|forested river corridors]] (e.g. the [[Yellowstone River|Yellowstone]] and [[Musselshell River|Musselshell]]), but increases in forests in the northern [[Great Plains]] decades later would allow them to connect their eastern and western distributions across southern Canada. These increases in forests were caused by [[European-American settlers]] via [[wildfire suppression]] and ceasing the fires historically set by [[Indigenous peoples of the Americas|Native Americans]], as well as by increased tree-planting.<ref name= Holt>{{cite journal|doi=10.2307/3536484|jstor=3536484 |last1=Holt |first1=Denver W. |last2=Domenech |first2=Rob |last3=Paulson |first3=Anne |title=Status and Distribution of the Barred Owl in Montana |journal=Northwestern Naturalist |date=2001 |volume=82 |issue=3 |pages=102–110 }}</ref>

In Canada, the barred owls with range expansion now range through southern [[Manitoba]] (excluding the southwest corner), a broad section of south-central [[Saskatchewan]], and east-central and nearly all of western [[Alberta]], now up to [[High Level, Alberta|High Level]].<ref name="iucn status 12 November 2021" /><ref name= Duncan>{{cite journal|author=Duncan, J. R., & Duncan, P. A.|year=1997|url=https://research.fs.usda.gov/treesearch/15626|title=Increase in distribution records of owl species in Manitoba based on a volunteer nocturnal survey using Boreal Owl (''Aegolius funereus'') and Great Gray Owl (''Strix nebulosa'') playback|editor1=Duncan, James R.|editor2=Johnson, David H.|editor3=Nicholls, Thomas H.|journal=Biology and Conservation of Owls of the Northern Hemisphere: 2nd International Symposium|publisher=Gen. Tech. Rep. NC-190. St. Paul, MN: US Dept. of Agriculture, Forest Service, North Central Forest Experiment Station|pages=519–524|volume=190}}</ref> The barred owl has been present in Manitoba at least since 1886, Alberta since 1932 and Saskatchewan since 1948.<ref>{{cite journal|last=Seton|first=E. E. T. |year=1886|title=The birds of western Manitoba|journal=Auk |volume=3|issue=3 |pages=145–156, 320–329|doi=10.2307/4625404
|jstor=4625404 |url=https://www.biodiversitylibrary.org/part/87645 }}</ref><ref>{{cite journal|last=Preble|first=E. A. |year=1941|title=Barred Owl on Athabaska River, Alberta|journal= The Auk |volume=58|issue=3 |pages=407–408|doi=10.2307/4078969 |jstor=4078969 |doi-access=free}}</ref><ref>{{cite journal|doi=10.29173/bluejay2494 |title=First Saskatchewan Nest Record of Barred Owl |date=1961 |last=Houston |first=Stuart |journal=Blue Jay |volume=19 |issue=3 |doi-access=free }}</ref> However, a study in Alberta has shown that barred owls have likely been present for no less than 100 years.<ref>{{cite journal|title=The Barred Owl, ''Strix varia'' in Alberta: distribution and status|date=2004 |doi=10.22621/cfn.v118i2.916 |last=Priestley |first=Lisa Takats |journal=The Canadian Field-Naturalist |volume=118 |issue=2 |page=215 |doi-access=free }}</ref> This owl species currently ranges through much of [[British Columbia]], where they have been expanding their range since at least 1943, including [[Vancouver Island]] and as far north as [[Fort St. John, British Columbia|Fort St. John]].<ref name= Campbell>{{cite book|author=Campbell, W., Dawe, N. K., McTaggart-Cowan, I., Cooper, J. M., Kaiser, G. W., & McNall, M. C.|year=2011|title=Birds of British Columbia, Volume 2: Nonpasserines-Diurnal Birds of Prey through Woodpeckers|publisher=UBC Press}}</ref><ref>{{cite journal|doi=10.2307/3536439|jstor=3536439 |title=The Barred Owl in British Columbia |last=Grant |first=James |journal=The Murrelet |date=1966 |volume=47 |issue=2 |pages=39–45 }}</ref> The barred owl has had a further northward expansion in the west to [[southeastern Alaska]] ([[Skagway, Alaska|Skagway]] to [[Ketchikan, Alaska|Ketchikan]]) and extreme southwestern [[Yukon]]. In the western United States they also range into northwestern [[Montana]] and northern [[Idaho]].<ref>{{cite book|author=Montana Bird Distribution Records Committee|year=1992|title=P. D. Skaar's Montana Bird Distribution|edition=4th|publisher=Montana Natural History Program|location=Helena, MT, USA}}</ref><ref>{{cite journal|author=Stephens, D. A., & Sturts, S. H.|year=1997|title=Idaho bird distribution: mapping by latilong|journal=Idaho Mus. Nat. Hist, Spec. Publ|issue=13}}</ref> Barred owls were first verified in southwest Montana in 1909 and in northwest Montana in 1921 (although reports of the species may date back to the 1870s) but not in Idaho until 1968.<ref name= Livezey2 /><ref name= Holt /> Of unknown origin, barred owls have been seen in [[Colorado]] since around the turn of the 20th century.<ref>{{cite journal|doi=10.2307/4069130|jstor=4069130 |last1=Nehrling |first1=H. |title=Bird Notes from Sao Paulo, Brazil |url=https://archive.org/details/sim_auk_1900-07_17_3/page/298|journal=The Auk |date=1900 |volume=17 |issue=3 |pages=298–299 }}</ref><ref>{{cite journal|doi=10.2307/4071272|jstor=4071272 |last1=Cooke |first1=Wells W. |title=The Birds of Colorado: Third Supplement |journal=The Auk |date=1909 |volume=26 |issue=4 |pages=400–422 |url=https://www.biodiversitylibrary.org/part/87307 }}</ref> They range broadly in eastern and western [[Washington (state)|Washington]] (reached by 1965) and western [[Oregon]] (reached by 1972) (mostly along the forested corridors hugging the [[montane]] areas of the [[Cascade Range|Cascade]], [[Olympic Mountains|Olympic]] and [[Blue Mountains (Pacific Northwest)|Blue]] ranges), and [[northern California]] (reached by 1976), now down to the [[Redwood National and State Parks|Redwood National Forest]], the [[Sierra Nevada (U.S.)|Sierra Nevada]] and outer [[San Francisco]].<ref>{{cite journal|author=Smith, M. R., Mattocks Jr., P.W. & Cassidy, K.M.|year=1997|title=Breeding birds of Washington State|journal=Washington State Gap Analysis – Final Report|editor1=K. M. Cassidy|editor2=C. E. Grue|editor3=M. R. Smith|editor4=K. M. Dvornich|publisher=Seattle Audubon Society Publications in Zoology no. 1.|location=Seattle, WA, USA}}</ref>

=== Habitat ===
[[File:Strix varia Barred Owl 3.8.2008.jpg|thumb|left|The barred owl usually makes its home in deciduous forests]]

The habitat used by barred owl is largely old [[Temperate deciduous forest|deciduous]], [[Temperate broadleaf and mixed forest|mixed forests]] and, occasionally, [[Temperate coniferous forest|coniferous forests]].<ref name= Konig /> [[Old growth forest]]s are preferred due to more extensive potential nest sites, less lower-branch density to impede hunting (and perhaps superior structural complexity to aid hunting), greater security from mobbing and perhaps greater [[thermoregulation]].<ref name= Nicholls>{{cite journal|doi=10.2307/3799054|jstor=3799054 |title=Barred Owl Habitat Use as Determined by Radiotelemetry |last1=Nicholls |first1=Thomas H. |last2=Warner |first2=Dwain W. |journal=The Journal of Wildlife Management |date=1972 |volume=36 |issue=2 |pages=213–224 |url=https://digital.library.unt.edu/ark:/67531/metadc1033926/ |doi-access=free }}</ref><ref name= McGarigal2>{{cite journal|doi=10.2307/3801804|jstor=3801804 |title=The Effect of Forest Stand Age on Owl Distribution in Southwestern Virginia |last1=McGarigal |first1=Kevin |last2=Fraser |first2=James D. |journal=The Journal of Wildlife Management |date=1984 |volume=48 |issue=4 |pages=1393–1398 }}</ref> They are often found in [[bottomland hardwood forest]]s in the largest swath of the native breeding range, often (particularly from [[Virginia]] south and west) with deep, dark stands of [[oak]], [[Nyssa sylvatica|gum]] and [[cypress]].<ref name= Voous /><ref name= Dickson>{{cite journal|author=Dickson, J. G. |year=1988|title=Bird communities in oak-gum-cypress forests|journal= Bird Conservation|volume= 3|pages= 51–62}}</ref> Secondary habitat, often used during foraging forays in the south, are often [[oak savanna]] or [[Sabal palmetto|cabbage-palm]] areas.<ref name= Voous /> Regardless of area, some variety of water is frequently present, including [[Riparian zone|riparian areas]] or [[swamp]]y ground.<ref name= Konig /><ref name= Bent /><ref name= Laidig>{{cite journal|url=https://biostor.org/reference/215761|author1=Laidig, K. J.|author2=Dobkin, D. S. |year=1995|title=Spatial overlap and habitat associations of barred owls and great horned owls in southern New Jersey|journal= Journal of Raptor Research|volume= 29|issue=3|pages=151–157}}</ref> Closed canopy forests were preferred in a study from [[Oklahoma]] (62.8% of habitat used), followed by [[fallow]] [[field (agriculture)|agricultural fields]] (10.6%), [[wetland]]s (8.1%) and [[open terrain]] (6.2%). The latter three were visited during hunting forays, and wetlands and open terrain areas were not used outside of the breeding season.<ref name= Winton>{{cite journal|author1=Winton, B. R.|author2= Leslie, D. M. |year=2004|title=Density and habitat associations of barred owls at the edge of their range in Oklahoma|jstor=3878075|journal= Southeastern Naturalist|volume= 3|issue=3|pages= 475–482|doi= 10.1656/1528-7092(2004)003[0475:DAHAOB]2.0.CO;2 |s2cid= 85726566 }}</ref> Along the [[East Coast of the United States|Atlantic coast]] area from [[New England]] to [[New Jersey]], barred owls are often found in mixed swamps areas with [[cedrus|cedars]], seldom wandering to adjacent [[wetland]]s or [[Agriculture|farmland]].<ref>{{cite journal|author1=Sutton, C. C.|author2=Sutton, P. T. |year=1986|title=The status and distribution of Barred Owl and Red-shouldered Hawk in southern New Jersey|journal= Cassinia|volume= 61|pages= 20–29|url=https://dvoc.org/CassiniaOnLine/Cassinia61/C61_20_29.pdf}}</ref><ref>Smith, C. F. (1978). ''Distributional ecology of Barred and Great Horned owls in relation to human distribution''. Master's Thesis, Univ. of Connecticut, Hartford.</ref> The species may be at home in wooded areas in [[Montane ecosystems|mountainous regions]].<ref name= Konig /> More upland wooded habitats, often in mixed woods containing [[Tsuga|hemlock]], [[alder]], [[Populus|poplar]], [[pine]] and [[oak]], are typical in the northern part of the range.<ref name= Hume /><ref name= Laidig /> A study in northern New Jersey found at least 15 species of both conifer and deciduous trees were routinely used for differing purposes.<ref>Rothauser, B. (2003). [https://www.nj.gov/dep/fgw/ensp/pdf/end-thrtened/barredowl.pdf ''Barred Owl, Strix varia'']. NJ Fish and Wildlife.</ref> In Michigan, barred owl habitat usually consists largely of some combination of hemlock and [[maple]] trees, with mixed forest usage being use disproportionately to its prevalence in the environment.<ref name= Elody>{{cite journal|author1=Elody, B. I.|author2= Sloan, N. F. |year=1985|title=Movements and habitat use of Barred Owls in the Huron Mountains of Marquette County, Michigan, as determined by radiotelemetry|journal= Jack-Pine Warbler|volume= 63|issue=1|pages= 3–8}}</ref> Large [[oak]] stands were preferred in [[Minnesota]], a bit ahead of mixed forest and far ahead of [[Thuja occidentalis|white cedar]] swamps and other habitat types, which were either too dense, too open or had too few attractive nesting sites.<ref name= Nicholls /><ref name= Fuller>Fuller, M. R. (1979). ''Spatiotemporal ecology of four sympatric raptor species''. Phd Thesis, Univ. of Minnesota, Minneapolis.</ref>

Barred owls are not confined to extensive forest, also dwelling extensively in semi-open [[Woodland|wooded areas]], locally in [[Park|large parks]] with mature trees, and in [[Habitat fragmentation|forest adjacent regions]] recently [[Logging|logged]].<ref name= Konig /> Recent studies show [[suburb]]an neighborhoods can be ideal habitat for barred owls, and the species may be considered a local [[synanthrope]].<ref name= Bierregaard>Bierregaard, R. O. (2018). "Barred Owls: a nocturnal generalist thrives in wooded, suburban habitats", pp. 138–151 in ''Urban Raptors''. Island Press, Washington, DC. {{ISBN|9781610918398}}</ref> Using transmitters, scientists found that some regional populations, such as in [[Charlotte, North Carolina]], increased faster in the [[suburb]]an settings than in [[old growth forest]]. A factor of this suburban success may be easily accessible [[rodent]] prey in such settings. However, for breeding and roosting needs, this species needs at least some large trees and can be locally absent in some urban areas for this reason. The increased offspring offset the death rate due to impacts from cars, other types of collisions and disease.<ref>{{cite web|url=http://www.livescience.com/animals/071017-urban-owls.html|title=Owls Get Wise to Better Life in Cities|first=Jeanna|last=Bryner|website=LiveScience|year=2007}}</ref> Similarly, in [[Piedmont, South Carolina]], productivity of the owls was higher in suburban areas and they comprised 41% of the territories of the local owls but various sorts of [[Human impact on the environment|anthropogenic]] mortality were seemingly higher.<ref>{{cite journal|doi=10.5751/ACE-01427-140212 |title=Key habitat features facilitate the presence of Barred Owls in developed landscapes |date=2019 |last1=Clement |first1=Marion A. |last2=Barrett |first2=Kyle |last3=Baldwin |first3=Robert F. |journal=Avian Conservation and Ecology |volume=14 |issue=2 |s2cid=202860589 |doi-access=free }}</ref> In suburban areas of [[Ohio]], 41.4% of barred owl range was forested, 29.8% was low-density residential areas and less than 15% was [[pasture]].<ref name="Dykstra">{{cite journal|doi=10.3356/JRR-11-05.1|title=Habitats of Suburban Barred Owls (''Strix varia'') and Red-Shouldered Hawks (''Buteo lineatus'') in Southwestern Ohio|date=2012 |last1=Dykstra |first1=Cheryl R. |last2=Simon |first2=Melinda M. |last3=Daniel |first3=F. Bernard |last4=Hays |first4=Jeffrey L. |journal=Journal of Raptor Research |volume=46 |issue=2 |pages=190–200 |s2cid=86775451 |doi-access=free }}</ref> On the other hand, studies from the [[Northeastern United States]], such as in [[New Jersey]], found barred owls breeding mainly in plots of old-growth woodlands, and rarely successfully breeding in [[Peri-urbanisation|peri-urban areas]], in part because of competitive and predatory displacement by [[great horned owl]]s.<ref name= Laidig /><ref name= Bosakowski>Bosakowski, T., Speiser, R., & Benzinger, J. (1987). ''Distribution, density, and habitat relationships of the Barred Owl in northern New Jersey''. Biology and Conservation of Northern Owls. Gen. Tech. Re, RM-142. US Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, Fort Collins, 135–143.</ref> Furthermore, a study in [[North Carolina]] showed most barred owls appear to favor areas with at least {{convert|86|to|370|ha|acre|abbr=on}} of woods but did not seem to be affected by the presence of roadways.<ref>Rubino, M. J. (2001). ''Identifying barred owl habitat in the North Carolina Piedmont: using GIS in focal species conservation planning'' (Master's thesis, North Carolina State University.).</ref>

In the [[Pacific Northwest]], they can be quite adaptive to [[secondary forest]]s.<ref name= BNA /> On the other hand, in [[Ontario]] where the barred owl is native, secondary forest seemed to be largely avoided per a study.<ref>Van Ael, S. M. (1996). ''Modelling Barred Owl habitat in northwestern Ontario''. Master's Thesis, Lakehead Univ., Thunder Bay, ON.</ref> In the recent western part of the range, barred owls often dwell in mixed wood areas, often where there are lowland stands of [[Populus balsamifera|balsam poplar]], [[Populus tremuloides|trembling aspen]] and [[Picea glauca|white spruce]], occasionally but not commonly in pure [[Pinophyta|conifer]] [[Boreal forest|boreal stands]].<ref name= Mazur2>Mazur, K. M., James, P. C., Fitzsimmons, M. J., Langen, G., & Espie, R. H. M. (1997). ''Habitat associations of the Barred Owl in the boreal forest of Saskatchewan, Canada''. Journal of Raptor Research, 31(3), 253–259.</ref><ref name= Takats>Takats, D. L. (1998). ''Barred Owl habitat use and distribution in the Foothills Model Forest''. Master's Thesis, Univ. of Alberta, Edmonton.</ref><ref name= Dunbar>{{cite journal|author1=Dunbar, D. L.|year=1991|title=Status of the spotted owl, ''Strix occidentalis'', and barred owl, ''Strix varia'', in southwestern British Columbia|journal=Canadian Field-Naturalist|volume=105|issue=4|pages= 464–468|doi=10.5962/p.358095 |doi-access=free}}</ref> Barred owls in California preferred stands of [[Alnus rubra|red alder]]. More so confined to inland areas, as in eastern Washington, Idaho, Manitoba and Montana, they prefer Douglas fir, [[Pinus ponderosa|ponderosa pine]], [[Betula papyrifera|paper birch]], [[Quercus macrocarpa|burr oak]] and [[Larix occidentalis|western larch]]. In north-central Alberta, the use of old growth forest was far more prevalent than its occurrence in the wild.<ref name= Olsen>Olsen, B. (1999). ''Breeding habitat ecology of the barred owl (Strix varia) at three spatial scales in the boreal mixedwood forest of north-central Alberta''. UNM. {{doi|10.7939/R3280575V}}</ref> In the [[Cascades Range]] of Washington, barred owls usually dwell in areas with more [[Abies grandis|grand firs]], taller and more diverse tree heights, more enclosed canopies, higher numbers of trees per acre and less ground cover.<ref>{{cite journal|doi=10.3356/rapt-49-02-129-140.1|author=Singleton, P. H. |title=Forest structure within barred owl (''Strix varia'') home ranges in the Eastern Cascade Range, Washington|journal=Journal of Raptor Research |date=2015 |volume=49 |issue=2 |pages=129–140 |s2cid=83958216 |doi-access=free }}</ref> In Saskatchewan, barred owls preferred areas with a minimum of 66% forest cover.<ref name= Grossman>{{cite journal|title=Responses of Great Horned Owls (''Bubo virginianus''), Barred Owls (''Strix varia''), and Northern Saw-whet Owls (''Aegolius acadicus'') to forest cover and configuration in an agricultural landscape in Alberta, Canada|date=2008 |doi=10.1139/Z08-095 |last1=Grossman |first1=S. R. |last2=Hannon |first2=S. J. |last3=Sánchez-Azofeifa |first3=A. |journal=Canadian Journal of Zoology |volume=86 |issue=10 |pages=1165–1172 }}</ref>

== Behavior ==
[[File:Barred Owl (Canada).jpg|thumb|Barred pattern, Ontario, Canada]]

The barred owl, like most owls, is largely adapted to [[nocturnality]].<ref name= Konig /> Between 5:00{{nbsp}}am and 8:00{{nbsp}} pm, juvenile barred owls were recorded to sleep an average of 28% of each hour.<ref>{{cite journal|author1=Hamerstrom, F.|author2=Janick, K. |year=1973|title=Diurnal sleep rhythm of a young barred owl|journal=The Auk|volume= 90|issue=4|pages= 899–900|doi=10.2307/4084377 |jstor=4084377 |doi-access=free}}</ref> Peak times in [[Minnesota]] were found to be right after sunset and just before dawn.<ref name= Tester>{{cite journal|author1=Tester, J. R. |year=1987|url=https://www.cedarcreek.umn.edu/biblio/fulltext/t1153.pdf|title=Changes in daily activity rhythms of some free-ranging animals in Minnesota|journal=Canadian Field-Naturalist|volume= 101|issue=1|pages=13–21|doi=10.5962/p.355849 }}</ref> Nonetheless, they are not as fully nocturnal as many owls and rank around 6th amongst 19 regular North American owl species for the regularity of their activity outside of nightfall, especially in particular circumstances such as when a rival or a human impersonator is emitting barred owls calls or whilst hunting. Often daytime activity tends to be early in the morning or around dusk but potentially at any time ([[overcast]] days being preferred).<ref name= Caldwell>{{cite journal|author1=Caldwell, L. D. |year=1972|title=Diurnal hunting by a Barred Owl|journal=Jack Pine Warbler |volume= 50|pages=93–94}}</ref><ref name= Jackson>{{cite journal|author1=Jackson, J. A.|author2= White, R. |year=1995|title=Diurnal roadside hunting by Barred Owls|journal= Journal of Louisiana Ornithology|volume= 3|pages= 13–15}}</ref><ref>{{cite journal|author1=Campbell, J. M. |year=1969|title=The owls of the central Brooks Range, Alaska|journal=The Auk|volume= 86|issue=3|pages= 565–568|doi=10.2307/4083428 |jstor=4083428 }}</ref> This species often spends the daytime hidden away in the dense foliage of a tree, often at minimum {{convert|5|m|ft|abbr=on}} above the ground, but sometimes also roosts in a branch close to a broad trunk or in a natural tree hollow.<ref name= Konig /><ref name= Voous /> Roost tree heights in [[Minnesota]] was typically {{convert|8|to|12|m|ft|abbr=on}} while, in [[Illinois]], they were up to {{convert|9|m|ft|abbr=on}}.<ref name= Blakemore>{{cite journal|author1=Blakemore, L. A. |year=1940|title=Barred Owl food habits in Glenwood Park, Minneapolis, Minnesota|journal= Flicker|volume= 12|pages= 21–23}}</ref><ref name= Applegate>{{cite journal|author1=Applegate, R. D. |year=1975|title=Co-roosting of Barred Owls and Common Grackles|journal= Bird-Banding |volume=46|issue=2 |pages= 169–170|doi=10.2307/4512120 |jstor=4512120 }}</ref> Recently fledged owls sometimes roost in tall grass, usually after falling from the nest tree.<ref name= Dunstan />

Roost site selection may be partially dictated by [[thermoregulation]], as in spotted owls, with shadier roosts likely to mitigate [[Hyperthermia|heat stress]].<ref>{{cite journal|author1=Barrows, C. W. |year=1981|title=Roost selection by Spotted Owls: an adaptation to heat stress|journal= Condor|volume= 83|issue=4 |pages= 302–309|doi=10.2307/1367496 |jstor=1367496 }}</ref> They seldom rely on [[camouflage]], instead often flying at the least disturbance and not allowing close approaches, making them potentially difficult to observe.<ref name= Hume /> Yet, on the other hand, they can be surprisingly tame and seemingly curious of people in the wild; further they are considered "as mild and engaging" as a predator can be.<ref name= Hume /> Barred owls are regularly subject to [[Mobbing (animal behavior)|mobbing]] by small birds, from several small [[passerine]]s to [[corvid]]s and [[woodpecker]]s, and mammals when discovered by them during the daytime, and such situations may lead to them being attacked by diurnal birds of prey.<ref name= Konig /><ref name= Bent /><ref>{{cite journal|author1=Carter, J. D. |year=1925|title=Behavior of the Barred Owl|journal=The Auk|volume=42|issue=3 |pages=443–444|doi=10.2307/4074397 |jstor=4074397 |doi-access=free}}</ref> There are some records of barred owls engaging in [[Preening (bird)|allopreening]], presumably between pairs, with each other in the wild.<ref>{{cite journal|author1=Fitzpatrick, J. W. |year=1975|title=A record of allopreening in the Barred Owl|journal=The Auk|volume=92|issue=3 |pages= 598–599|doi=10.2307/4084622 |jstor=4084622 |doi-access=free}}</ref><ref>{{cite journal|author1=Scott, D. |year=1980|title=Owls allopreening in the wild|journal= British Birds|volume= 73|pages= 436–39}}</ref> They are skilled and silent fliers and frequently use routine forest flyways with open understory and low branch densities.<ref name= Nicholls/>

[[File:Strix varia DM1.jpg|thumb|left|The barred owl is normally nocturnally active and sleeps during the day]]

Like most species of owl in the ''Strix'' genus, the barred owl tends to be highly [[Territory (animal)|territorial]] regardless of the time of year.<ref name= Konig /><ref name= McGarigal2 /><ref name= Mosher /><ref name= Nicholls /> The territories are claimed by singing from different perches, often near the perimeter of its perceived home range. The boundaries are almost always well-maintained by barred owls and are generally stable from year to year and even generation to generation.<ref name= Nicholls /> Territory sizes have been determined via [[Wildlife radio telemetry|radio telemetry]].<ref name= Konig /> The average territory size of 13 in Minnesota was {{convert|273|ha|acre|abbr=on}}, of 7 in Michigan it was {{convert|282|ha|acre|abbr=on}} and of 10 in Wisconsin was {{convert|337.9|ha|acre|abbr=on}}.<ref name= Olsen /><ref name= Nicholls /> Another Minnesota study found pairs to occupy a mean of about {{convert|226|ha|acre|abbr=on}} in mixed hardwood-conifer woods.<ref name= Konig /> Pairs in an Oklahoma study were reportedly found every {{convert|110|to|165|ha|acre|abbr=on}}.<ref name= Winton /> The mean territory size from 10 studies was estimated from throughout the range. In this study, the breeding season mean area was calculated at {{convert|256.7|ha|acre|abbr=on}} in males and {{convert|297.8|ha|acre|abbr=on}} in females; whereas the means in nonbreeding season were {{convert|900.4|ha|acre|abbr=on}} in males and {{convert|536.2|ha|acre|abbr=on}} in females. Overall, the annual mean home range for males was {{convert|782|ha|acre|abbr=on}} and for females was {{convert|538.7|ha|acre|abbr=on}}.<ref name= Livezey5 /> The breeding range's mean home size in Washington was {{convert|321|ha|acre|abbr=on}}, while it was {{convert|971|ha|acre|abbr=on}} in the non-breeding season.

[[File:Barred owl bathing.webm|thumb|right|Barred owl bathing in Brett Woods, [[Fairfield, Connecticut]]]]
The ranges of pairs overlaps in the breeding season, at 87–95% range overlap, but decreases down to 45% after hatching.<ref name="Fuller"/> In a Florida study of barred owls, territorial responses, including several [[duet]]s, by a pair were found to be provoked by researchers playing calls of both "stranger" owls and recordings of owls that were neighbors to the pair being tested. The aggressive response even to known neighbors in this study is unusual.<ref name="Mennill">{{cite journal |last1=Mennill |first1=Daniel |last2=Odom |first2=Karan |date=2010 |title=Vocal duets in a nonpasserine: An examination of territory defence and neighbour–stranger discrimination in a neighbourhood of barred owls |journal=Behaviour |volume=147 |issue=5–6 |pages=619–639 |doi=10.1163/000579510X12632972452424}}</ref> In [[tawny owl]]s in a study from [[Italy]], for instance, they responded mildly or not at all to the calls of neighboring tawny owls known to them but with great aggression to the calls of "stranger" owls.<ref>{{cite journal|doi=10.1111/j.1474-919X.1993.tb02847.x|title=Differential responses of territorial Tawny Owls ''Strix aluco'' to the hooting of neighbours and strangers|date=2008 |last1=Galeotti |first1=Paolo |last2=Pavan |first2=Gianni |journal=Ibis |volume=135 |issue=3 |pages=300–304 }}</ref> Due to its rather stolidly territorial nature, the barred owl is not normally a migratory species.<ref name= Konig /> Claims in the past of "rather impressive" flights in [[New England]] in the past were lacking in verifiable details.<ref name= Voous /> Of 158 banded recoveries in the northern part of the range, movements during winter were found to cover no further than {{convert|10|km|mi|abbr=on}}, while all those recovered in Saskatchewan and Alberta scarcely moved at all.<ref name= Johnsgard /><ref name= Campbell /><ref name= Mazur3>Mazur, K. M. (1997). [https://www.nlc-bnc.ca/obj/s4/f2/dsk3/ftp04/mq30518.pdf ''Spatial habitat selection by Barred Owls in the boreal forest of Saskatchewan, Canada'']. Master's Thesis, Univ. of Regina, Regina, SK.</ref> There is little to no evidence of nomadic behavior as has been recorded in several other owls in the north.<ref name= Nicholls2>Nicholls, T. H. & Fuller, M. R. (1987). ''Territorial Aspects of Barred Owl Home Range and Behavior in Minnesota''. In ''Biology and Conservation of Northern Forest Owls: Symposium Proceedings''. February 3–7, 1987, Winnipeg, Manitoba (Vol. 142, p. 121). Fort Collins, Colo.: Rocky Mountain Forest and Range Experiment Station.</ref><ref name= Elody2>Elody, B. I. (1983). ''Techniques for capturing, marking, monitoring, and habitat analysis for the Barred Owl in the Upper Peninsula of Michigan''. Master's Thesis, Michigan Technological Univ., Houghton.</ref>

== Dietary biology ==
[[File:Barred 2010 3 web.jpg|thumb|left|Small mammals tend to be the characteristic prey for barred owls]]

Barred owls are opportunistic predators of the woodlands. Like the tawny owl, the barred owl usually hunts from a perch. During hunting efforts, they glide briefly from perch to perch until prey is detected.<ref name= Konig /><ref name= Hume /> The barred owl has incredibly large eyes that capture as much light as possible, allowing for better night vision. Attacks may be carried out merely {{convert|6|to|10|m|ft|abbr=on}} away from the prey due to the effectiveness of the silencing wing feathers.<ref>Lilley, G. (1998).  ''A study of the silent flight of the owl''. In 4th AIAA/CEAS aeroacoustics conference (p. 2340).</ref> The barred owl, especially compared to the predominantly [[Arboreal locomotion|arboreal]] prey of the spotted owl, usually prefers to target small animals that are [[Terrestrial animal|terrestrial]].<ref name= Wiens>{{cite journal|doi=10.1002/wmon.1009 |title=Competitive interactions and resource partitioning between northern spotted owls and barred owls in western Oregon |date=2014 |last1=Wiens |first1=J. David |last2=Anthony |first2=Robert G. |last3=Forsman |first3=Eric D. |journal=Wildlife Monographs |volume=185 |issue=1 |pages=1–50 |bibcode=2014WildM.185....1W }}</ref> However, barred owls will also flush and capture night-roosting birds, and capture bats on the wing as well.<ref name= Konig /> Daytime hunting has been reported several times, although peak hunting time is typically shortly after sunset.<ref name= Bent /><ref name= Caldwell /><ref name= Jackson /><ref name= Sutherland>{{cite journal|url=https://sora.unm.edu/node/138641|author1=Sutherland, D. A.|author2= Jones, I. L. |year=2010|title=Successful Diurnal Foraging by a Barred Owl|journal=Ontario Birds|volume=28|issue=3|pages=152–155}}</ref> Although they usually hunt within woodlands, they also occasionally hunt in [[open terrain]], more typical of the hunting areas of a bird like the long-eared owl.<ref name= Hume /> Cases of snow-plunging have been verified for barred owls, allowing them to capture prey like [[vole]]s in [[Subnivean climate|subnivean zones]] that they use as hidden [[snow]] tunnels during winter, a hunting method once thought particular to [[great grey owl]]s.<ref>{{cite journal|doi=10.29173/bluejay5428 |title=Evidence of Snow-Plunging by Boreal and Barred Owls |date=1993 |last1=Nero |first1=Robert W. |journal=Blue Jay |volume=51 |issue=3 |s2cid=221969147 |doi-access=free }}</ref> While hunting [[American red squirrel|squirrels]] in the [[Alberta–British Columbia foothills forests|Foothill Model Forest]] of [[Alberta]], barred owls were seen to make several passes before succeeding.<ref name= Takats2>{{cite journal|author=Takats, D. L. |year=1996|title=Foraging observations of a Barred Owl in the Foothills Model Forest|journal= Alberta Naturalist |volume=26|pages= 29–30}}</ref> Hunting on the ground is usually done to obtain foods such as [[invertebrate]]s or [[amphibian]]s.<ref name= Dunstan /><ref name= Elderkin>Elderkin, M. F. (1987). ''The breeding and feeding ecology of a Barred Owl Strix varia Barton population in Kings County, Nova Scotia''. Master's Thesis, Acadia Univ., Wolfville, NS.</ref> These owls may wade into shallow water to capture fish and may do an unusual amount of aquatic foraging, as compared to any ''Strix'' species or North American owl.<ref name= Konig /><ref name= Hume />

Due to its relatively modest foot size, it does not usually take particularly large prey.<ref name= Hume /> However, owls in general have proportionately larger feet and more powerful [[Flexor digitorum longus muscle|grips]] than similarly sized diurnal raptors, while the physiology of the [[Accipitridae|daytime raptors]] [[Flexor hallucis longus muscle|differs]]. While the mechanism of the killing feet overlap, owls kill mainly with [[constriction]] and sacrifice [[velocity]] with their physiology while diurnal raptors have higher velocity and kill mainly by [[Major trauma|trauma]] inflicted by their enlarged talons.<ref name= Ward>{{cite journal|doi=10.1093/auk/119.4.1052 |title=Functional Morphology of Raptor Hindlimbs: Implications for Resource Partitioning |date=2002 |last1=Ward |first1=Andrea B. |last2=Weigl |first2=Peter D. |last3=Conroy |first3=Rachael M. |journal=The Auk |volume=119 |issue=4 |pages=1052–1063 |doi-access=free }}</ref> A majority of prey of barred owls is eaten outright but, with large prey, the barred owl may eat the head first and then return to consume the remainder of the body.<ref name= Elderkin /> Cases of owls of any variety [[Scavenger|scavenging]] on [[carrion]] are generally rare, but at least three instances of carrion-feeding by barred owls have been observed, more recently eating [[White-tailed deer|deer]] and [[Eastern gray squirrel|squirrel]] [[roadkill]]s on a remote camera in North Carolina.<ref>{{cite journal|title=Carrion-feeding by Barred Owls (''Strix varia'')|jstor=23033577 |last1=Kapfer |first1=Joshua M. |last2=Gammon |first2=David E. |last3=Groves |first3=John D. |journal=The Wilson Journal of Ornithology |date=2011 |volume=123 |issue=3 |pages=646–649 |doi=10.1676/11-015.1 |s2cid=85768266 }}</ref><ref>Forbush, E. H. (1925). ''Birds of Massachusetts and other New England states. Volume 2''. Massachusetts Department of Agriculture, Boston, US.</ref> The [[Pellet (ornithology)|pellet]] of the barred owl averages about {{convert|3.5|cm|in|abbr=on}} in diameter and {{convert|7.2|cm|in|abbr=on}} in length.<ref name= BNA />

[[File:Bird lore (1908) (14750520262).jpg|thumb|A 1908 photo of a site found with a massive amount of barred owl casts and pellets near [[Carlisle, Pennsylvania]]]]

The barred owl has been known to consume a diversity of animals from different [[Class (taxonomy)|taxonomic classes]]. Primarily, these owls live off of small [[mammal]]s.<ref name= Konig /><ref name= Mikkola /> Other [[vertebrate]]s are rarely neglected though, especially [[bird]]s and [[amphibian]]s, but also occasionally [[reptile]]s and [[fish]]. For an owl its size, the barred owl also consumes a large amount of [[arthropod]]s and other [[invertebrate]]s.<ref name= Konig /><ref name= Livezey5>{{cite journal|author=Livezey, K.B.|year= 2007|title=Barred Owl habitat and prey: a review and synthesis of the literature |journal= Journal of Raptor Research |doi=10.3356/0892-1016(2007)41[177:BOHAPA]2.0.CO;2|volume=41|issue= 3|pages=177–201|s2cid= 86266928|url= https://zenodo.org/record/1236455|doi-access=free}}</ref><ref name= Worm>{{cite journal |author=Livezey, K.B. |author2=Elderkin, M.F. |author3=Cott, P.A. |author4=Hobbs, J. |author5=Hudson, J.P. |year= 2008|title= Barred owls eating worms and slugs: the advantage in not being picky eaters|jstor=30135134|journal= Northwestern Naturalist |doi=10.1898/NWN08-04.1|volume=89|issue= 3|pages=185–190|s2cid= 86062164}}</ref><ref name="fcps.edu">[http://www.fcps.edu/islandcreekes/ecology/barred_owl.htm ''Barred Owl''] {{Webarchive|url=https://web.archive.org/web/20171027093706/http://www.fcps.edu/islandcreekes/ecology/barred_owl.htm |date=2017-10-27 }}. Fcps.edu. Retrieved on 2016-08-01.</ref> One study from a wide swath of the range found that among 2234 accrued prey items, 76% were mammals, 15.8% were invertebrates, 5.8% were birds and 2.5% were other vertebrates.<ref name= Snyder>Snyder, N. F., & Wiley, J. W. (1976). ''Sexual size dimorphism in hawks and owls of North America (No. 20)''. American Ornithologists' Union.</ref> In four other studies from different parts of the distribution, the mean balance of mammals in diet was around 64.9%, birds at around 13.4%, invertebrates at around 11.4% and different classes of vertebrates (mostly amphibians) at around 10.3%.<ref name= BNA /><ref name= Takats /><ref name= Elderkin /><ref name= Marks>{{cite journal|doi=10.2307/3534209|jstor=3534209 |title=Winter Food Habits of Barred Owls in Western Montana |last1=Marks |first1=Jeffrey S. |last2=Hendricks |first2=D. Paul |last3=Marks |first3=Victoria S. |journal=The Murrelet |date=1984 |volume=65 |issue=1 |pages=27–28 }}</ref><ref name= Bosakowski2>{{cite journal|doi=10.1139/z92-140 |title=Comparative diets of sympatric nesting raptors in the eastern deciduous forest biome |date=1992 |last1=Bosakowski |first1=Thomas |last2=Smith |first2=Dwight G. |journal=Canadian Journal of Zoology |volume=70 |issue=5 |pages=984–992 }}</ref> A compilation study that included a total of 7077 prey items using all methodologies, 71.9% were mammals, 9.5% were birds, 0.6% reptiles, 6% amphibians, 1.89% fish, 1% [[earthworm]]s, 0.2% [[gastropod]]s, 6.5% [[insect]]s and 2.4% [[crayfish]].<ref name= Livezey5 /> Barred owls tend to focus on fairly small-sized prey, although are capable of attacking larger than usual prey in infrequent cases.<ref name= Wiens /><ref name= Livezey5 /> The mean size of prey taken is seldom estimated in the barred owls' eastern range, although one study estimated mean size of prey in the general east was {{convert|33.5|g|oz|abbr=on}}.<ref name= Marti>{{cite book|doi=10.1007/978-1-4615-9582-3_2|isbn=978-1-4615-9582-3 |chapter=Trophic Structure of Raptor Communities: A Three-Continent Comparison and Synthesis |title=Current Ornithology |date=1993 |last1=Marti |first1=Carl D. |last2=Korpimäki |first2=Erkki |last3=Jaksić |first3=Fabian M. |pages=47–137 }}</ref> Many more studies have estimated mean prey masses in westerly areas of sympatry with spotted owls to understand how their diets may conflict.<ref name= Wiens /> Different studies from the west (mainly [[Washington (state)|Washington]] and [[Oregon]]) have variously estimated the mean prey sizes for barred owls at {{convert|47.7|g|oz|abbr=on}}, {{convert|56.1|g|oz|abbr=on}}, {{convert|60.2|g|oz|abbr=on}}, {{convert|103.5|g|oz|abbr=on}} and {{convert|123.6|g|oz|abbr=on}}.<ref name= Wiens /><ref name= Marti /><ref name= Graham>Graham, S. A. (2012). [https://core.ac.uk/download/pdf/61724451.pdf ''Diet composition, niche and geographic characteristics, and prey size preference of Barred Owls (Strix varia) in the Pacific Northwest'']. Masters Thesis, Oregon State University.</ref><ref name= Hamer>{{cite journal |author=Hamer, T.E. |author2=Hays, D.L. |author3=Senger, C.M. |author4=Forsman, E.D. |year= 2001|title= Diets of northern barred owls and northern spotted owls in an area of sympatry|journal= Journal of Raptor Research |url=https://sora.unm.edu/node/53893|volume=35|pages=221–227}}</ref>

=== Mammals ===
The predominant small mammals available in forest and woodland edges are generally small [[rodent]]s, so the barred owl, like other ''Strix'' owls, most often relies on rodents as the primary type of food.<ref name="Livezey5" /> Preferred rodents to be taken are [[vole]]s, [[Mouse|mice]] of the genus ''[[Peromyscus]]'' and assorted [[rat]]s, including non-native ''[[Rattus]]'' species as well as unrelated native types like [[cotton rat]]s, [[Oryzomys|rice rats]] and [[Pack rat|woodrats]]. These all share with barred owls a penchant for [[nocturnality]] and [[Crepuscular animal|crepuscular]] habits (although many voles are more correctly considered [[Cathemerality|cathemeral]])<ref name="Konig" /><ref name="Voous" /><ref name="Johnsgard" /> While during other seasons, the diet of barred owls can be fairly diverse, the winter diet may be almost wholly rodents.<ref name="Livezey5" /> This was the case in winter in [[Montana]], where 97.6% of 1153 prey items were [[montane vole]]s or [[meadow vole]]s, with a possible slight mixture of other voles.<ref name= Holt2>{{cite journal|doi=10.1898/1051-1733(2007)88[7:BOWDAP]2.0.CO;2|issn=1051-1733 |date=2007 |volume=88 |page=7 |title=Barred Owl Winter Diet and Pellet Dimensions in Western Montana |last1=Holt |first1=Denver W. |last2=Bitter |first2=Colleen |journal=Northwestern Naturalist |s2cid=86350479 }}</ref> The diet of barred owls in a much smaller study near [[Urbana, Illinois]] during winter was less homogeneous but still led by rodents, especially the meadow vole (32.3%) and [[white-footed mouse]] (23.5%).<ref name= Cahn>{{cite journal|doi=10.2307/4075480|jstor=4075480 |last1=Cahn |first1=Alvin R. |last2=Kemp |first2=Jack T. |title=On the Food of Certain Owls in East-Central Illinois |journal=The Auk |date=1930 |volume=47 |issue=3 |pages=323–328 }}</ref> A winter food study in [[Essex County, New Jersey]] found that among 118 prey items, meadow voles comprised a great majority of the prey, at 91.5% of the balance.<ref name= Rusling>{{cite journal|author=Rusling, W. J. |year=1951|title=Food habits of New Jersey owls|journal=Proc. Linnaean Soc. New York|volume=58–62|pages=38–45}}</ref>

An unusual lack of diversity in barred owl pellets was found in several years of possibly an aseasonal study in [[Ann Arbor, Michigan]] where of 777 prey items, 83.3% were meadow voles.<ref name= Wilson>{{cite journal|doi=10.2307/4078196|jstor=4078196 |last1=Wilson |first1=Kenneth A. |title=Owl Studies at Ann Arbor, Michigan |journal=The Auk |date=1938 |volume=55 |issue=2 |pages=187–197 |doi-access=free }}</ref> At Edwin S. George Preserve near the [[University of Michigan]], the summer diet was also heavily rodent based, as among 146 prey items 37.9% were white-footed mice, 22.6% were [[southern bog lemming]] and 6.84% were meadow voles.<ref name= Hamerstrom>{{cite journal|author1=Hamerstrom Jr, F. N.|author2= Hamerstrom, F. |year=1951|title=Food of young raptors on the Edwin S. George Reserve|url=https://sora.unm.edu/node/127017 |journal=The Wilson Bulletin|pages= 16–25}}</ref> In a somewhat larger Michigan study, the [[North American deermouse]], lead the prey at 34.9% of 321 prey items.<ref name= Errington>{{cite journal|doi=10.2307/1363563|jstor=1363563 |last1=Errington |first1=Paul L. |title=Food Habits of Southern Wisconsin Raptors. Part I. Owls |journal=The Condor |date=1932 |volume=34 |issue=4 |pages=176–186 }}</ref> In [[Minnesota]], the barred owl was counted as one of the leading causes of mortality of [[prairie vole]]s.<ref>{{cite journal|doi=10.1093/jmammal/17.3.291|title=''Microtus ochrogaster'' in Minnesota |url=https://archive.org/details/sim_journal-of-mammalogy_1936-08-14_17_3/page/290|date=1936 |last1=Allan |first1=P. F. |journal=Journal of Mammalogy |volume=17 |issue=3 |page=291 }}</ref> Studies of the barred owl diet in 6 urban [[metropolitan area|metropolitan]] areas of [[British Columbia]] found that the diet was dominated by young rats of the invasive ''[[Rattus]]'' genus, comprising 52.8% of 688 prey items, well ahead of native [[Townsend's vole]]s, which were secondary at 19.2% of the diet. The average weight rats taken by owls were clearly juveniles, estimated to average {{convert|103|g|oz|abbr=on}}, although several could be anywhere from infant rat to adult rat sizes, i.e. about {{convert|25|to|300|g|oz|abbr=on}}.<ref name= Hindmarch>{{cite journal|doi=10.3356/jrr-14-00012.1 |title=When Owls go to Town: The Diet of Urban Barred Owls |date=2015 |last1=Hindmarch |first1=Sofi |last2=Elliott |first2=John E. |journal=Journal of Raptor Research |volume=49 |pages=66–74 |s2cid=59379580 |doi-access=free }}</ref> The mean size of [[black rat]]s taken in Oregon was {{convert|250|g|oz|abbr=on}}, indicating that here large adults of this species were selected.<ref name= Graham /> Beyond the typical more meadow-dwelling voles and woodland edge-dwelling native mice, larger and more forest dwelling rodents of different varieties can be of variable import.<ref name= BNA /><ref name= Hamer /> Numerous [[Pack rat|woodrat]] species may be taken and may provide a hearty meal to a barred owl, at a mean body mass when taken (in [[Oregon]]) of {{convert|285|g|oz|abbr=on}} for unidentified species.<ref name= Wiens /><ref name= Graham /><ref>{{cite journal|title=Observed Predation of ''Neotoma magister'' (Allegheny Woodrat) by ''Strix varia'' (Barred Owl) in Virginia|date=2020 |doi=10.1656/045.027.0103 |last1=Powers |first1=Karen E. |last2=Dimas |first2=Miranda S. |last3=Leon |first3=Angie I. |last4=Vanmeter |first4=Logan M. |journal=Northeastern Naturalist |volume=27 |s2cid=213605365 }}</ref><ref>{{cite journal|author=HaySmith, L. |year=1995|title=''Neotoma floridana floridana'': natural history, populations, and movements in northcentral Florida|journal= Bulletin of the Florida Museum of Natural History|volume= 38|pages= 211–243|doi=10.58782/flmnh.gdie1905 |url=https://www.floridamuseum.ufl.edu/wp-content/uploads/sites/35/2017/03/Vol-38-No-8.pdf}}</ref>

In different areas, barred owls may regularly hunt the diverse members of the [[squirrel]] family, despite their general penchant for [[diurnality]]. Smaller squirrel varieties are usually focused on when hunted as supplement prey, such as [[chipmunk]]s, averaging about {{convert|83|g|oz|abbr=on}} among the different species they prey upon, and [[pine squirrel]]s, which average about twice as large as chipmunks.<ref name= Takats /><ref name= Wiens /><ref name= Graham /><ref name= Merritt>{{cite journal|url=http://ilacadofsci.com/wp-content/uploads/2013/12/106-12MS1305Final.pdf|author1=Meritt, D. A. Jr.|author2= Eul, R. |year=2013|title=Barred Owl pellet contents in Michigan|journal= Illinois State Academy of Science. Transactions|volume= 106|page= 55}}</ref> Usually juvenile specimens are focused on when taking the larger ''[[Sciurus]]'' [[tree squirrel]]s, at least in summer, but presumably a mixture of yearling and adult ''Sciurus'' will be taken during winter.<ref name= Wiens /> The mean weight of [[western gray squirrel]]s taken during the breeding season in Oregon was {{convert|450|g|oz|abbr=on}}, against a mean adult weight of around {{convert|770|g|lb|abbr=on}}.<ref name= Graham /><ref>{{cite journal |last1=Hayssen |first1=Virginia |title=Patterns of Body and Tail Length and Body Mass in Sciuridae |journal=Journal of Mammalogy |date=15 August 2008 |volume=89 |issue=4 |pages=852–873 |doi=10.1644/07-MAMM-A-217.1|s2cid=29249283 |doi-access=free }}</ref> The issue of temporal activities is less pertinent to the predator of [[flying squirrel]]s, which are nocturnal. All studies of the diet of barred owls in [[Pacific Northwest]] show the importance of the [[northern flying squirrel]] to their diet. This flying squirrel was found to comprise from about 10.9% to 20% of the diet of barred owls (either as the most or second most important prey species) and, with a mean weight of {{convert|134|g|oz|abbr=on}} when taken, they comprised up to 25.6% of the food [[Biomass (ecology)|biomass]] for this owl species.<ref name= Wiens /><ref name= Graham /><ref name= Hamer /> In [[Green Ridge State Forest]] in [[Maryland]], although not numerically the most important prey family compared to unidentified cricetids and shrews, the [[southern flying squirrel]] was the most often identified prey species for barred owls.<ref name= Devereux>{{cite journal|author1=Devereux, J. G.|author2= Mosher, J. A. |year=1984|title=Breeding ecology of Barred Owls in the central Appalachians|journal= Raptor Research|volume= 18|issue=2|pages=49–58|url=https://biostor.org/reference/216646}}</ref> Beyond the aforementioned rodent prey, more infrequently rodent prey can including various other [[Cricetidae|cricetid rodents]], [[pocket gopher]]s, [[mountain beaver]]s (average weight when taken of up to {{convert|550|g|lb|abbr=on}}) and [[jumping mice]].<ref name= Wiens /><ref name= Blakemore /><ref name= Graham /> The largest known rodent prey of barred owls are adult [[muskrat]], which were estimated to weigh {{convert|1169|g|lb|abbr=on}} when taken.<ref name= Graham />

[[File:Barred owl (Strix varia) dining on a mole.webm|thumb|left|A barred owl consuming a mole (possibly a [[coast mole]]) in [[Washington (state)|Washington]]]]

The other primary mammalian prey types are the [[shrew]]s and the [[Mole (animal)|moles]]. At least a dozen species of shrew and most North American species of mole are known as prey of the barred owl.<ref name= Sutherland /><ref name= Livezey5 /><ref name= Wiens /><ref name= Graham /> 12.8% of 7077 total prey items from across the range were [[Eulipotyphla|shrews or moles]].<ref name= Livezey5 /> A small sample of prey in [[Michigan]] was led by the very small [[masked shrew]], which weighs around {{convert|4|g|oz|abbr=on}}, at 24% of 34 prey items.<ref name= Merritt /> A much larger shrew, the [[northern short-tailed shrew]] at around {{convert|21|g|oz|abbr=on}}, was the leading prey in [[Glenwood, Minnesota]] at 36% of 81 prey items.<ref name= Blakemore /> This prey species also is taken quite regularly in several other parts of the range, as well as a [[Southern short-tailed shrew|closely-related species]].<ref name= Devereux /> Assorted other shrew species and the smallest of the world's moles, the [[American shrew mole]] are regular supplement prey elsewhere, especially in the Pacific Northwest.<ref name= Wiens /><ref name= Graham /><ref name= Hamer /> The most frequently taken single prey species through the Pacific Northwest, at 11.8% of 4299 total prey items of barred owls, was the {{convert|56|g|oz|abbr=on}} [[coast mole]].<ref name="Wiens" /> Usually, moles are secondary if relatively hearty prey elsewhere in the range.<ref name="Whiklo2">Whiklo, T. (2012). ''Nest structure and breeding habitat characteristics of Barred Owls (Strix varia) in Manitoba, Canada''. {{hdl|1993/5218}} {{doi|10.13140/RG.2.2.32357.19682}}</ref>

Secondary prey can include several species of [[cottontail rabbit]]s (''Sylvilagus'' sp.) and [[snowshoe hare]]s (''Lepus americanus'').<ref name= Wiens /><ref>{{cite journal|doi=10.2307/3799058|jstor=3799058 |title=Twenty Years of Avian Predator-Small Mammal Relationships in Missouri |last1=Korschgen |first1=Leroy J. |last2=Stuart |first2=Henry B. |journal=The Journal of Wildlife Management |date=1972 |volume=36 |issue=2 |pages=269–282 }}</ref> 3.2% of 7077 prey items from across the range for barred owls were [[Lagomorpha|rabbits or hares]].<ref name= Livezey5 /> Among cottontails, small juveniles are largely taken, but rabbits as large as an adult [[brush rabbit]]s can be taken.<ref name= Errington /><ref name= Graham /> The weights of snowshoe hares taken by barred owls in the Pacific Northwest were estimated at ranging from {{convert|50|g|lb|abbr=on}} leverets to juveniles and standard-sized adults about {{convert|1200|to|1400|g|lb|abbr=on}}.<ref name= Wiens /><ref name= Graham /><ref name= Hamer />

[[Bat]]s are infrequently reported as prey in most of the range but an unusually close association was detected in [[Valdosta, Georgia]], where most of the prey, 65% of pellet contents and 37 total bats, were [[southeastern myotis]] (''Myotis austroriparius'').<ref>{{cite journal|doi=10.1656/058.016.0110 |title=Bats as Predominant Food Items of Nesting Barred Owls |date=2017 |last1=Bergstrom |first1=Bradley J. |last2=Smith |first2=Marvin T. |journal=Southeastern Naturalist |volume=16 |pages=N1–N4 |s2cid=89723777 }}</ref> Barred owls are also known predators of small mammalian [[carnivora]]ns, mainly [[mustelid]]s such as [[stoat]]s (''Mustela erminea'') and [[long-tailed weasel]]s (''Neogale frenata'').<ref>{{cite journal|title=Survival and predation of weasels (''Mustela erminea'', ''Mustela frenata'') in North America|date=2017 |doi=10.3955/046.091.0104 |last1=Linnell |first1=Mark A. |last2=Epps |first2=Clinton W. |last3=Forsman |first3=Eric D. |last4=Zielinski |first4=William J. |journal=Northwest Science |volume=91 |pages=15–26 |s2cid=89860715 }}</ref> Predation on small [[American mink]] (''N. vison'') have also been reported.<ref name= Errington/> As they are seemingly not affected by strong odor, [[eastern spotted skunk|eastern spotted]] and [[western spotted skunk]]s (''Spilogale gracilis'' & ''S. putorius'') of all ages can be taken.<ref name= Graham /><ref>{{cite journal|title=Eastern spotted skunk (''Spilogale putorius'') survival and cause-specific mortality in the Ouachita Mountains, Arkansas|date=2010 |doi=10.1674/0003-0031-164.1.52 |last1=Lesmeister |first1=Damon B. |last2=Millspaugh |first2=Joshua J. |last3=Gompper |first3=Matthew E. |last4=Mong |first4=Tony W. |journal=The American Midland Naturalist |volume=164 |pages=52–60 |s2cid=83621716 }}</ref><ref>{{cite journal|doi=10.1656/058.020.0sp1111 |title=Genetic Confirmation of Predation of an Adult Female Eastern Spotted Skunk by a Barred Owl |date=2021 |last1=Hassler |first1=Kendyl N. |last2=Kessinger |first2=Brin E. |last3=Harms |first3=Caroline E. |last4=Price |first4=Lucas E. |last5=Barton |first5=Ethan P. |last6=Oxenrider |first6=Kevin J. |last7=Rogers |first7=Rich E. |last8=Pearce |first8=Kelly J. |last9=Serfass |first9=Thomas L. |last10=Welsh |first10=Amy B. |journal=Southeastern Naturalist |volume=20 |s2cid=236999938 }}</ref><ref>{{cite journal|doi=10.1898/1051-1733-103.3.250 |title=Barred Owl Predation of Western Spotted Skunks |date=2022 |last1=Tosa |first1=Marie I. |last2=Lesmeister |first2=Damon B. |last3=Levi |first3=Taal |journal=Northwestern Naturalist |volume=103 |issue=3 |s2cid=253667556 }}</ref> Much larger mammals are sometimes recorded in the foods of barred owls, but there are few details known about the age, condition, or circumstances (i.e. they may have been consumed as [[carrion]] or, perhaps more likely, young or infirm specimens were taken).<ref name= Livezey5 /> Some such prey species recorded have included the [[Virginia opossum]], the [[North American porcupine]],<ref name= Marks /> the [[striped skunk]]<ref name= Voous /> and the [[Cat|domestic cat]]. Adults of all these species are known to count amongst the prey of great horned owls which are better suited than barred owls to take particularly large prey given its more robust morphology.<ref>{{cite book|last=Smith|first=Dwight G.|title=Great Horned Owl|year=2002|publisher=Stackpole Books|location=Mechanicsburg, PA |url=https://books.google.com/books?id=f1PVJVWbQKwC |isbn=978-0-8117-2689-4 |pages=33, 80–81 |edition=1st }}</ref>

=== Birds ===
[[File:Hermit thrush (27991992249).jpg|thumb|right|Barred owls will eat fledglings of the [[hermit thrush]]<ref name= Streby/>]]

Throughout the barred owl's range, other birds are taken as prey, although avian species make up a much smaller proportion of their diets than mammals. The maximum known representation of bird prey in a barred owl food study was 25.1% in [[Alberta]], meaning that they augment their diet less heavily with bird prey than their near equivalent in Europe, the [[tawny owl]].<ref name= BNA /><ref>Glue, D. E. (1972). ''Bird prey taken by British owls''. Bird Study, 19(2), 91–96.</ref><ref>{{cite journal|doi=10.1002/ece3.3899 |title=What determines prey selection in owls? Roles of prey traits, prey class, environmental variables, and taxonomic specialization |date=2018 |last1=Comay |first1=Orr |last2=Dayan |first2=Tamar |journal=Ecology and Evolution |volume=8 |issue=6 |pages=3382–3392 |pmid=29607033 |pmc=5869362 |bibcode=2018EcoEv...8.3382C }}</ref> No specific variety of bird is subject to the most frequent predation by barred owls and birds are the most diverse class in these owl's prey spectrum, with more than 100 species of bird known to be hunted.<ref name= Bent /><ref name= Livezey5 /><ref name= Wiens /> Conspicuous nesting sites of [[barn swallow]] and [[purple martin]] on manmade structures and objects were revealed via video-monitoring to suffer heavy predation by barred owls. In the case of the barn swallows, all ages of swallow as well as possibly eggs were eaten. 65 of 95 monitoring barn swallow nests were consumed by owls over a 3-year period.<ref>{{cite journal|title=Evidence of Barred Owls (''Strix varia'') Depredating Nests of Barn Swallows (''Hirundo rustica'')|date=2017 |jstor=26456083|doi=10.1676/16-054.1 |last1=Mahony |first1=Nancy A. |journal=The Wilson Journal of Ornithology |volume=129 |issue=3 |pages=641–644 |s2cid=89785198 }}</ref><ref>{{cite journal|url=https://www.researchgate.net/publication/292148462|author=Ray, J. D. |year=2014|title=Avian predation on Purple Martins nesting in artificial housing|journal= Bull. Texas Ornith. Soc|volume= 47|pages= 1–2}}</ref> The [[Bank (geography)|muddy bank]] nests of [[American cliff swallow|cliff swallows]] are also vulnerable to barred owls, while other swallow species are known to be opportunistically taken.<ref>{{cite journal |last1=Hamilton |first1=Gary D. |last2=Martin |first2=Robert F. |title=Investigator Perturbation and Reproduction of the Cliff Swallow |journal=The Auk |date=January 1985 |volume=102 |issue=1 |pages=167–170 |doi=10.2307/4086836|jstor=4086836 }}</ref>

In more enclosed wooded areas, radio-tagging and [[Camera trap|video-monitoring]] of various passerines nests as well as examinations of owl pellets has shed light on the relationship of barred owls with these potential prey resources. Not only was the barred owl found to be a surprisingly routine predator at woodland passerine nests, but that an unexpected bulk of the acts of predation in studies from Missouri and Illinois were carried out during the daytime. Many different forest bird species (most frequently [[Acadian flycatcher]]s and [[indigo bunting]]s in Missouri and Illinois) were hunted. These studies indicated that the barred owl may snatch passerines of any age, but recent fledglings are taken preferentially due to their more conspicuous behavior and limited ability to fly away. In Minnesota, about 62% of studied [[hermit thrush]] and [[ovenbird]] fledglings were taken per one study, with all thrush that nested in the {{convert|50|m|ft|abbr=on}} radius of the barred owl's nests failing to produce any young. A similarly high rate of local determent by barred owls has been found for other woodland thrushes like the [[veery]], [[wood thrush]] and [[varied thrush]], with the additional finding that pre-dawn singing by certain thrushes, when their escape abilities are dulled by the dim light, leaves them vulnerable to barred owl ambushes.<ref name= Takats /><ref name= Gill>{{cite journal |last1=Gill |first1=Ryan A. |last2=Cox |first2=W. Andrew |last3=Thompson |first3=Frank R. |title=Timing of Songbird Nest Predation as Revealed by Video Surveillance |journal=The Wilson Journal of Ornithology |date=March 2016 |volume=128 |issue=1 |pages=200–203 |doi=10.1676/1559-4491-128.1.200|s2cid=86980126 }}</ref><ref name= Streby>{{cite journal |last1=Streby |first1=Henry M. |last2=Refsnider |first2=Jeanine M. |last3=Peterson |first3=Sean M. |last4=Andersen |first4=David E. |title=Barred Owl Predation on Hermit Thrush and Ovenbird Fledglings |journal=Journal of Raptor Research |date=December 2008 |volume=42 |issue=4 |pages=296–298 |doi=10.3356/JRR-08-10.1|s2cid=83697804 }}</ref><ref>{{cite journal |last1=Schmidt |first1=Kenneth A. |last2=Rush |first2=Scott A. |last3=Ostfeld |first3=Richard S. |title=Wood thrush nest success and post-fledging survival across a temporal pulse of small mammal abundance in an oak forest |journal=Journal of Animal Ecology |date=July 2008 |volume=77 |issue=4 |pages=830–837 |doi=10.1111/j.1365-2656.2008.01378.x|pmid=18355240 |doi-access=free |bibcode=2008JAnEc..77..830S }}</ref> Forest birds seem to recognize the barred owl as a threat, with mobbing behavior evoked easily by playing recordings of their calls in the daytime.
[[File:Ruffed Grouse (1).jpg|thumb|left|Ruffed grouse are known prey in extensive parts of the range]]

A wide diversity of bird prey may be occasionally hunted by barred owls in different circumstances. Smaller or mid-sized bird prey species known have including different species, though usually a relatively low species diversity and in low numbers, beyond swallows and thrushes of [[tyrant flycatcher]]s, [[vireo]]s, [[chickadee]]s, [[wren]]s, [[mimid]]s, [[Piranga|tanagers]], other [[Cardinalidae|cardinalids]] and [[finches]].<ref name= Bent /><ref name= Graham /> Somewhat higher diversity of species are known from the [[American sparrow|sparrow]] and [[New World warbler|warbler]] families.<ref name= Gill /><ref>Anich, N. M., T. J. Benson, J. D. Brown, C. Roa, J. C. Bednarz, R. E. Brown, and J. G. Dickson (2020). "Swainson's Warbler (''Limnothlypis swainsonii'')", version 1.0. In ''Birds of the World'' (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref><ref>Sherry, T. W., R. T. Holmes, P. Pyle, and M. A. Patten (2020). ''American Redstart (Setophaga ruticilla)'', version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> Birds down to the size of the [[calliope hummingbird]], North America's smallest hummingbird at {{convert|2.7|g|oz|abbr=on}}, may be taken by barred owls.<ref name= Wiens /> At the opposite end of passerine prey for barred owls, this species will sometimes take all ages of the [[American crow]], from very young nestlings to adults.<ref name= BNA /> Numerous non-passerine birds are also taken, though seldom in great numbers and of low known species diversity.<ref name= Livezey5 /> One exceptional family is the [[woodpecker]]s, which are probably so widely taken because of their generally overlapping habitat preferences with those of barred owls. Several species of woodpecker are preyed upon almost throughout the range, including at least a half dozen in Oregon alone, from the smallest North American species, the [[downy woodpecker]], to the largest, the [[pileated woodpecker]].<ref name= Graham /><ref name= Fisher>Fisher, A. K. (1893). ''The hawks and owls of the United States in their relation to agriculture'' (No. 3). US Department of Agriculture, Division of Ornithology and Mammalogy.</ref> Other small-to-medium-sized bird species known as prey for barred owls are: [[mountain quail]], [[grey partridge]], [[rock dove]], [[band-tailed pigeon]], [[mourning dove]], [[American purple gallinule|purple gallinule]], [[killdeer]], [[American woodcock]], [[least tern]], [[snowy egret]],<ref>Parsons, K. C. and T. L. Master (2020). "Snowy Egret (''Egretta thula'')", version 1.0. In ''Birds of the World'' (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> [[cattle egret]]<ref>Telfair II, R. C. (2020). "Cattle Egret (''Bubulcus ibis''), version 1.0. In ''Birds of the World'' (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> and [[belted kingfisher]]. Although they take many chicks of gamebirds, adults of these species are vulnerable as well.<ref name= Bent /> In many areas, [[ruffed grouse]] are not infrequently taken, comprising up to nearly 6% of prey items in Alberta. In Oregon, the weights estimated for ruffed grouse taken by barred owls varied enormously, from small chicks estimated at {{convert|25|g|oz|abbr=on}}, to adults weighing about {{convert|576|g|lb|abbr=on}}. Broader study in the Pacific Northwest indicated that adult ruffed grouse were mainly taken.<ref name= Takats /><ref name= Wiens /><ref name= Graham /><ref>{{cite journal |last1=Mangelinckx |first1=Joelle M. |last2=Brown |first2=Samantha R. |last3=Allen |first3=R. Bradford |last4=Sullivan |first4=Kelsey |last5=Blomberg |first5=Erik J. |title=Effects of forest characteristics on ruffed grouse nesting ecology in central Maine, USA |journal=Wildlife Biology |date=14 February 2020 |volume=2020 |issue=1 |doi=10.2981/wlb.00598|s2cid=211567501 |doi-access=free }}</ref> Barred owls are also known to take adult [[spruce grouse]] of about the same size as the ruffed grouse, as well as much larger species including the [[common pheasant]] and the [[sooty grouse]], the latter estimated to average {{convert|1050|g|lb|abbr=on}} when taken.<ref name= Marks /><ref name= Graham /><ref>Schroeder, M. A., E. J. Blomberg, D. A. Boag, P. Pyle, and M. A. Patten (2020). "Spruce Grouse (''Falcipennis canadensis'')", version 1.0. In ''Birds of the World'' (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> Barred owls are also known to prey on the young of other, larger birds, such as the [[American white ibis]] and [[wild turkey]].<ref>Hingtgen, T. M., Mulholland, R., & Repenning, R. W. (1985). [https://www.usgs.gov/publications/habitat-suitability-index-models-white-ibis ''Habitat suitability index models: white ibis'']. Fish and Wildlife Service.</ref><ref>{{cite journal|doi=10.1002/jwmg.21267 |title=Nest site selection and nest survival of eastern wild turkeys in a pyric landscape |date=2017 |last1=Yeldell |first1=Nathan A. |last2=Cohen |first2=Bradley S. |last3=Little |first3=Andrew R. |last4=Collier |first4=Bret A. |last5=Chamberlain |first5=Michael J. |journal=The Journal of Wildlife Management |volume=81 |issue=6 |pages=1073–1083 |bibcode=2017JWMan..81.1073Y |url=https://digitalcommons.unl.edu/natrespapers/731 |url-access=subscription }}</ref>

=== Other prey ===
Barred owl predation on reptiles is widely reported but they seldom take large numbers in any given area.<ref name= Livezey5 /> Most reported instances of such captures are of various small [[lizard]]s, often of [[skink]]s in the genus ''[[Plestiodon]],'' most often from the [[Midwest]] to the western parts of the range.<ref name= Bent /><ref name= Blakemore /> Several reported instances of barred owls hunting [[snake]]s are also known, but they are perhaps even more seldom preyed upon than lizards.<ref name= Bent /><ref name= Graham /> More than a half dozen snake species are known to be captured, several of which are [[Colubridae|colubrids]], which are mostly harmless.<ref>Conant, R. (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition''. Boston: Houghton Mifflin.</ref><ref>{{cite journal|author1=Meshaka, W. E. Jr.|author2= Layne, J. N. |year=2015|url=https://www.herpconbio.org/Volume_10/Monographs/Meshaka_Layne_2015-small.pdf |title=The herpetology of southern Florida|journal=Herpetological Conservation and Biology|volume= 10|issue=5|pages=1–353}}</ref><ref>Platt, D.R. (1969). [https://webapps.fhsu.edu/ksherp/bibFiles/10.pdf ''Natural history of the hognose snakes Heterodon platyrhinos and Heterodon nasicus'']. Univ. Kansas Publ. Mus.</ref> The estimated body mass of [[Coluber constrictor|black racer]] taken in Oregon was only {{convert|77|g|oz|abbr=on}}, well under their mean mature size.<ref name="Graham" /> However, consumption or predation on dangerous [[pit viper]]s, such as [[timber rattlesnake]]s and [[Agkistrodon contortrix|copperheads]], by barred owls has been reported, although it is not known whether these are taken as adults.<ref name="Voous" /><ref name="Bent" /><ref>Ernst, C. H., & Ernst, E. M. (2011). ''Venomous Reptiles of the United States, Canada, and Northern Mexico: Crotalus (Vol. 2)''. JHU Press.</ref> Rarer still is barred owl predation on [[turtle]]s.<ref name= Livezey5 /> Predation by this species was reported upon a very young [[river cooter]], which had a carapace width of only {{convert|31.4|mm|in|abbr=on}}, as well as on juvenile [[gopher tortoise]] and apparently [[diamondback terrapin]].<ref name="Bent" /><ref>{{cite journal|url=https://sora.unm.edu/node/137555|author=Peterson, S.W. |year=1989|title=Barred owl eats hatchling Turtle|journal=Mississippi Kite|volume= 19 |issue=2|pages=4–5}}</ref><ref>{{cite journal|doi=10.2307/1564605|title=Estimates of survival for juvenile gopher tortoises, ''Gopherus polyphemus''|jstor=1564605 |last1=Wilson |first1=Dawn S. |journal=Journal of Herpetology |date=1991 |volume=25 |issue=3 |pages=376–379 }}</ref> Much more characteristic than any reptilian prey are [[amphibian]]s, with various types of [[frog]]s, [[salamander]]s and similar species reported in this owl's foods.<ref name="Bent" /><ref name="Livezey5" /> Amphibians were considerably more popular in the diet in western part of range, comprising 10.5% of known studies against 4.4% in the east.<ref name="Livezey5" /> In total, well over 20 amphibian species have been identified in the foods of barred owls and amphibians collectively can make up to 24.5% of the local diet (as was reported in Alberta).<ref name="BNA" /><ref name="Takats" /><ref name="Livezey5" /> While salamanders and newts are probably often visually discerned while scanning the forest floor, many frogs are probably hunted down by sound during their crepuscular choruses.<ref name="Johnsgard" />

Amphibians are taken almost entirely during the breeding season, as they become unavailable to barred owls during the winter months.<ref name="Wiens" /><ref name="Graham" /> Most reported amphibian prey in Oregon were unidentified "medium-sized salamanders". A diversity of frog sizes may be taken, varying potentially in size from [[spring peeper]]s, which average around {{convert|4|g|oz|abbr=on}}, to [[American bullfrog]]s, which average around in mature bullfrogs {{convert|430|g|oz|abbr=on}}.<ref>{{cite web|url=http://animals.nationalgeographic.com/animals/amphibians/spring-peeper.html|archive-url=https://web.archive.org/web/20070614110143/http://animals.nationalgeographic.com/animals/amphibians/spring-peeper.html|archive-date=June 14, 2007|title=Spring Peeper Profile|publisher=[[National Geographic Society]]|access-date=2020-04-21}}</ref><ref>{{cite journal |author=Frost, D.R. |author2=Grant, T. |author3=Faivovich, J. |author4=Bain, R.H. |author5=Haas, A. |author6=Haddad, C.F.B. |author7=De Sá, R.O. |author8=Channing, A. |author9=Wilkinson, M. |author10=Donnellan, S.C. |author11=Raxworthy, C.J. |author12=Campbell, J.A. |author13=Blotto, B.L. |author14=Moler, P. |author15=Drewes, R.C. |author16=Nussbaum, R.A. |author17=Lynch, J.D. |author18=Green, D.M. |author19=Ward, C. |author20=Wheeler, W.C. |title=The Amphibian Tree of Life|journal=Bulletin of the American Museum of Natural History|volume=297|pages=1–291|doi=10.1206/0003-0090(2006)297[0001:TATOL]2.0.CO;2|hdl=2246/5781|year=2006|s2cid=86140137 |doi-access=free }}</ref> A notable act of successful predation was carried out by a barred owl on a [[rough-skinned newt]], which contains [[toxin]]s that are often deadly to predators. Apparently, the owl was able to survive after consuming the newt.<ref>{{cite journal|title=Rough-skinned newt (''Taricha granulosa'') predation by Barred Owls (''Strix varia'')|date=2018 |doi=10.1676/17-052.1 |last1=Medina |first1=Shelby L. |last2=Higley |first2=Mark |last3=Dumbacher |first3=John P. |journal=The Wilson Journal of Ornithology |volume=130 |issue=3 |pages=780–783 |s2cid=91731949 }}</ref> The rarest variety of vertebrate prey for barred owls is fish.<ref name= Livezey5 /> However, there are several accrued accounts of fishing by these owls, including older accounts of barred owls coming to [[Ice fishing|ice holes]] made by human [[fishermen]] and more recent accounts of possibly routine fishing by the owls on the [[St. Johns River]] in Florida, in the latter case utilizing a fishing [[dock (maritime)|dock]] as a hunting perch.<ref name= Bent /><ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/jfo/v054n01/p0088-p0089.pdf|author1=Smith, D. G.|author2=Devine, A.|author3= Devine, D. |year=1983|title=Observations of fishing by a Barred Owl|journal=Journal of Field Ornithology|pages= 88–89}}</ref> At least five species of fish have been identified in the foods of barred owls, including fairly large fish like [[brown bullhead]]s and [[largemouth bass]].<ref name= Voous /><ref name= Bent /><ref name= Graham />

[[File:Wood Frog - Lithobates sylvaticus, Lake Accotink Park, Springfield, Virginia (39440713811).jpg|thumb|left|Frogs such as [[wood frog]]s are a regular prey source for barred owls]]

The balance of assorted [[invertebrate]]s in the diet of barred owls can be quite high. Although many of those found in pellets are unidentified to species, nearly 40 species of invertebrates have been found in their foods.<ref name= Bent /><ref name= Livezey5 /><ref name= Graham /> Broad studies indicate [[arthropod]]s (including [[millipede]]s and [[spider]]s but predominantly [[insect]]s) in general comprise up to about 16% of the barred owl's foods.<ref name= Snyder /><ref name= Wiens /> When hunting [[insect]]s, barred owls most often prefer ground-based [[beetle]]s. In Oregon, 11.7% of the diet was assorted beetles (14 species were identified), being somewhat more numerous among 3686 prey items than other non-rodent prey orders.<ref name= Graham /> However, some insects prey such as [[luna moth]], [[Papilio glaucus|eastern tiger swallowtail]] and [[green darner]] are presumably [[Hawking (birds)|hawked]] on the wing around dawn and dusk.<ref name="Voous" /><ref name="Livezey5" /> It is known that barred owls will sometimes come hunt near manmade light sources and [[campfire]]s, flying out from the perch to quickly capture flying insects that were attracted to them.<ref name="Bent" /><ref name="Fisher" /> Of 123 prey items found in southern Manitoba, flying [[Sphingidae|Sphinx moths]] and flightless [[Phyllophaga|scarab beetles]] each comprised 7% (most of the remaining balance being unidentified mammals and birds). [[Crayfish]] of at least four identified species are another widely taken type of invertebrate, presumably snatched up by barred owls from shallow waterways.<ref name="Livezey5" /><ref name="Graham" /><ref name="Blakemore" /><ref>{{cite journal|jstor=24321812|author=VanArman, P. G. |year=2011|title=Role of native crayfish, '''Procambarus alleni'' (Faxon) and ''Procambarus fallax'' (Hagen), in everglades food webs: a literature review and conceptual model|journal= Florida Scientist|pages= 100–125|volume= 74|issue= 2}}</ref> Crayfish seem to be exclusively taken in the east and Midwest, areas where they comprised 3.4% of all known food studies, and none at all were recorded in the western part of the range.<ref name="Livezey5" /> In [[Missouri]], annually up to 31.1% (though, in some years, 0%) of the diet comprised crayfish. Barred owls occasionally feed on [[snail]]s and [[slug]]s, the latter especially in the Pacific Northwest.<ref name= Konig /><ref name= Worm /> Another snail, the [[Monadenia fidelis|Pacific sideband]], was surprisingly often present in the foods in Oregon as at least 135 were taken.<ref name= Graham /> Beyond slugs, other "soft" invertebrates are sometimes hunted, especially [[earthworm]]s. Earthworms were most prominent in the foods of barred owls in [[Nova Scotia]], where 27.6% of 186 video-monitored prey deliveries in Nova Scotia were worms, the most regularly delivered of all prey types there.<ref name= Elderkin /><ref name= Worm />

=== Interspecies predatory relationships ===
The barred owl's range overlaps with multiple other predators of similar prey species. Due to the time period barred owls are active, the most interaction occurs with other owl species. Of the owls in North America, about three-quarters are reliant on similar small mammal prey, usually rodents, with a mixture of other prey genera as supplements.<ref name= Weidensaul /> Other than its ecology where it today co-exists with spotted owls, however, there is some level of [[niche differentiation]] from a majority of sympatric owls.<ref name= Voous /> In the eastern forest biome, the barred owl is the only large owl species to dwell mainly in continuous forest areas.<ref name= Voous /><ref name= BNA /><ref name= Marti /> While many of the owls sympatric with barred owls over majority of their eastern and Midwestern range share a preference for hole-nesting, smaller hole-nesting owls usually prefer different habitats, such as the open country-dwelling [[Barn-owl|barn owl]] and the [[screech owls]], which usually in North America dwell at the interface of forest and open habitats.<ref name= Voous /><ref name= Johnsgard /> Both North American species in the ''[[Aegolius]]'' owl genus are forest-dwelling cavity nesters but are much smaller and are at entirely different [[trophic level]]s.<ref name= Voous /><ref name= Johnsgard /><ref name= Grossman />

A singular diurnal raptor species that mirrors the barred owl at nearly all ecological levels is the [[red-shouldered hawk]]. Both species have similar distributions, habitat preferences and somewhat similar dietary habits and trophic level. They may considered as nearly nocturnal and diurnal [[Ecological niche|ecological equivalents]].<ref name= BNA /><ref>Portnoy, J. W., & Dodge, W. E. (1979). ''Red-shouldered Hawk nesting ecology and behavior''. The Wilson Bulletin, 104–117.</ref> In multiple parts of the range, including southwestern Ohio, North Carolina and northern Michigan, the paralleling habitat usage and nesting behavior of the barred owl and red-shouldered hawk has been noted. One of the few respects in which their habitat usage differs is that the barred owl is more adaptive to nesting in suburban areas if they have old growth trees that provide plentiful [[tree hollow]]s. In contrast, red-shouldered hawks tend to avoid suburban areas whilst nesting, but may acclimate to these areas during the winter. Barred owls seldom alter their range throughout the year and remain more or less constrained to the stands they used during nesting.<ref name= Dykstra /><ref>Mason, J.S. (2004). [https://www.ospreytrax.com/Osprey_Migration/abstract.htm ''The reproductive success, survival, and natal dispersal of Barred Owls (Strix varia) in rural versus urban habitats in and around Charlotte, North Carolina'']. M.S. thesis, University of NC.</ref><ref name= Postupalsky>Postupalsky, S., Paap, J. M. & Scheller, L. (1997). "Nest sites and reproductive success of Barred Owls (''Strix varia'') in Michigan". Pages 325–337 in ''Biology and Conservation of Owls in the Northern Hemisphere: Second International Symposium''. J. R. Duncan, D. H. Johnson, and T. H. Nicholls (eds). USDA Forest Service General Technical Report NC-190.</ref> The red-shouldered hawk averages somewhat smaller and has a more limited diet than barred owls, but probably goes after dangerous prey such as snakes more regularly.<ref name= Voous /><ref name= Bent /><ref>{{cite journal|url=https://www.biodiversitylibrary.org/page/56868268#page/82/mode/1up|author=Roble, S. M. |year=2013|title=Ophiophagy in Red-shouldered Hawks (''Buteo lineatus''), with the First Record of Eastern Wormsnakes (''Carphophis amoenus'') as Prey|journal= Banisteria |volume=41|pages=80–84}}</ref> Multiple occasions are recorded where the barred owl and red-shouldered hawk have nested in the same area, often within the same grove of trees, remarkably with little to no conflict.<ref name= BNA /><ref name= Johnsgard /> At least one nest was found including eggs from both species.<ref name= Bent /> When nesting near other hawks like [[red-tailed hawk]]s and [[Cooper's hawk]]s, the relationship tends to be much more contentious between hawk and owl, despite barred owls sometimes sharing space or using the old nests of these hawks.<ref name= Voous /> A wing-clapping display by a pair of barred owls was recorded during antagonistic encounters in Manitoba with a pair of [[broad-winged hawk]]s. Wing-claps were previously not recorded in this species, and when recorded for other owl species were often for the purposes of courtship displays.<ref>{{cite journal|title=Occurrences of wing clapping behavior in Barred Owls (''Strix varia'')|date=2012 |doi=10.3356/JRR-12-18.1 |last1=Whiklo |first1=Todd M. |last2=Duncan |first2=James R. |journal=Journal of Raptor Research |volume=46 |issue=4 |pages=413–416 |s2cid=86567181 }}</ref>

[[File:Great Horned Owl on Seedskadee National Wildlife Refuge (22312850906).jpg|thumb|left|[[Great horned owl]]s are the most severe competitor and predator of barred owls]]

One predator that is a major source of conflict for the barred owl is the [[great horned owl]].<ref name= BNA /> In every part of their range, barred owls are compelled to share space with the larger owls.<ref name= Voous /> There is habitat partitioning between the barred owl and great horned owl that allows them to often co-exist. Great horned owls prefer various more open habitats mixed with trees, often in rather upland areas, which differs from the habitats preferred by the barred owl.<ref name= Voous /><ref name= Johnsgard /> If a great horned owl moves into an area, barred owls appear to avoid said areas, based on radio telemetry data.<ref name= Laidig /> In much of the east, habitat alteration and fragmentation tends to favor the great horned owl at the expense of the barred owl. Where more continuous forest is available, however, the great horned and barred owl can occur surprisingly close to one another. In one case, a barred owl was observed to roost only {{convert|400|m|ft|abbr=on}} from a great horned owl.<ref name= Laidig /><ref>{{cite journal|doi=10.2307/4079048|jstor=4079048 |last1=Baumgartner |first1=Frederick M. |title=Territory and Population in the Great Horned Owl |journal=The Auk |date=1939 |volume=56 |issue=3 |pages=274–282 |doi-access=free }}</ref> In general the [[reforestation]] at the northern sections of the [[Great Plains]] have, on the contrary, benefited barred owls (and may have been a part of allowing their westward expansion) and been perhaps slightly detrimental to the great horned owl.<ref name= Holt /> However, even where the habitat becomes less ideal, the great horned owl is unlikely to vacate an area, unlike the barred owl which can be entirely displaced if woods become too small and fragmented.<ref name= BNA /><ref name= Duncan /> Great horned owls and barred owls have similar diets, as both are wide-ranging, large and opportunistic owls.<ref name= Weidensaul /><ref name= Johnsgard /> However, the great horned owl is larger in bulk, sometimes averaging nearly twice as heavy, with much heavier, larger feet and talons.<ref name= Voous /><ref name= Snyder /> The great horned owl has a more powerful grip strength<ref name= Ward /> and access to a wider variety of prey than barred owls, which take fewer prey species because they occur in more limited habitats and have a smaller overall distribution.<ref name= Voous /><ref name= Bent /><ref name= Marti /><ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/condor/v076n01/p0045-p0061.pdf|author=Marti, C. D. |year=1974|title=Feeding ecology of four sympatric owls|journal= The Condor|volume= 76|issue=1|pages=45–61|doi=10.2307/1365983 |jstor=1365983 }}</ref><ref name= Earhart/> A study utilizing [[Stable isotope ratio|stable isotopes]] in Alberta appeared to confirm that the great horned owl preys on nearly twice as many prey species as do the barred owls of the area.<ref>Duxbury, J. M., & Holroyd, G. L. (1997). "You are what you eat: stable isotope ecology of owl diets in Alberta, Canada". In: Duncan, James R.; Johnson, David H.; Nicholls, Thomas H., eds. ''Biology and conservation of owls of the Northern Hemisphere: 2nd International symposium''. Gen. Tech. Rep. NC-190. St. Paul, MN: US Dept. of Agriculture, Forest Service, North Central Forest Experiment Station. 148–154. (Vol. 190).</ref>

The great horned owl is indeed likely to be the greatest natural enemy of the barred owl.<ref name= Voous /><ref name= Bent /> There are several accounts of the horned owl species preying on nestlings, fledglings and adults of the barred.<ref name= BNA /><ref name= Bent /><ref name= Fuller /><ref>{{cite journal|url=http://www.wildlifebc.org/pdfs/2_2_VanDamme.pdf|author = Van Damme, L. M. |year=2005|title=Diet of the great horned owl in the Creston Valley, British Columbia, 1998–2005|journal= Wildlife Afield|volume= 2 |issue=2|pages=73–78}}</ref> Other than horned owls, predation of the barred owl seems to be fairly rare outside of the nestling age, both due to the owl's relatively large size and their nesting habits, most often in secluded tree hollows.<ref name= BNA /> One more virulent nest predator is likely to be [[raccoon]]s (''Procyon lotor''), which can nearly decimate both tree hollow and stick nest locations of almost any kind of bird, especially in [[Peri-urbanisation|peri-urban]] areas where they largely exist without controlling predators.<ref name= Elderkin /><ref>Haskell, D. G., Knupp, A. M., & Schneider, M. C. (2001). "Nest predator abundance and urbanization", pp. 243–258 in ''Avian ecology and conservation in an urbanizing world''. Springer, Boston, MA. {{doi|10.1007/978-1-4615-1531-9_11}} {{ISBN|978-1-4615-1531-9}}</ref> Both the [[American marten]] and the [[Fisher (animal)|fisher]] are known to be nest predators of barred owls, in turn appearing to cause the owls to switch nest sites.<ref>Mazur, K. M., James, P. C., & Frith, S. D. (1997). [https://research.fs.usda.gov/treesearch/15497 "Barred Owl (''Strix varia'') nest site characteristics in the boreal forest of Saskatchewan, Canada"]. US DEPARTMENT OF AGRICULTURE FOREST SERVICE GENERAL TECHNICAL REPORT NC, 267–271.</ref> Other birds of prey may be an occasional threat to barred owls. [[Northern goshawk]]s have reportedly killed both young and adult barred owls.<ref name= BNA /><ref name= Bent /> One modern account mentions predation by a goshawk on a nestling barred owl (i.e. weight about {{convert|392|g|oz|abbr=on}}).<ref>{{cite journal|url=https://www.researchgate.net/publication/228635407|author1=Smithers, B. L.|author2= Boal, C. W.|author3=Andersen, D. A. |year=2005|title=Northern Goshawk diet in Minnesota: an analysis using video recording systems|journal=Journal of Raptor Research|volume= 39|issue=3|page=264}}</ref> A well-known instance of a goshawk attack on an adult barred owl concluded with the owl and goshawk killing one another.<ref name= Voous /><ref>{{cite journal|author=Eifrig, G. |year=1907|title=American Goshawk (''Accipiter atricapillus'') versus Man and Barred Owl|url=https://sora.unm.edu/node/8564|journal=The Auk|pages= 437–438}}</ref> There are some very rare, singular cases of predation on barred owls (age unknown) by [[red-tailed hawk]]s, which nonetheless generally appears to be a less menacing co-inhabitant than the goshawk.<ref name= Bent /><ref name= Shupe>{{cite journal|url=https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2218&context=nebbirdrev|author=Shupe, S. |year=1985|title=Observations of the Barred Owl in southeastern Nebraska|journal=Nebraska Bird Review|pages= 37–38}}</ref> More surprisingly, a [[Cooper's hawk]], a smaller species of raptor, was observed to apparently prey upon a full-grown barred owl in British Columbia.<ref>{{cite journal|author=Stirling, D. |year=2011|title=Cooper's Hawk Feeding on Barred Owl and Norway Rat in Victoria, British Columbia|journal= Wildlife Afield |volume=8|issue=1|pages=120–122|url=http://www.wildlifebc.org/pdfs/aug%202012/Stirling8.1Red.pdf}}</ref> An [[American alligator]] was reported to have preyed on a barred owl in at least one instance.<ref>Neill, W. T. (1971). ''The Last of the Ruling Reptiles''. Columbia University Press, New York, NY, USA.</ref>

On the other hand, the barred owl is a significant predator of smaller raptor species as well. Most smaller owls that co-exist with barred owls are at occasional risk of predation.<ref name= Voous /> A particular cause of concern in intraguild predations{{Definition needed|date=July 2020}} by the barred has been their encroachment into the areas inhabited by [[western screech owl]] (''Megascops kennicotti''). Several instances of predation have been noted on the screech owls and the recent, unprecedented presence of the barred owls appears to have a correlation with the decline of the western screech owl in British Columbia and in [[Bainbridge Island, Washington]].<ref name= Graham /><ref>{{cite journal|url=https://bcbirds.files.wordpress.com/2016/08/bcbirds_v14_p2_declining-numbers-of-western-screech-owl-in-the-lower-mainland-of-british-columbia.pdf|author=Elliott, K. |year=2006|title=Declining numbers of Western Screech-Owl in the lower mainland of British Columbia|journal= British Columbia Birds|volume= 14|pages= 2–11}}</ref><ref>{{cite journal|doi=10.1898/nwn11-21.1 |title=Recent Trends in Western Screech-Owl and Barred Owl Abundances on Bainbridge Island, Washington |date=2012 |last1=Acker |first1=Jamie |journal=Northwestern Naturalist |volume=93 |issue=2 |pages=133–137 |s2cid=85889087 }}</ref> In one instance, a biologist who called in an [[eastern screech owl]] (''Megascops asio'') in Ohio observed it to be immediately captured and consumed by a barred owl. The barred owl is a serious predator of eastern screech owls, but is less deadly to them in general than the great horned owl.<ref>Ritchison, G., F. R. Gehlbach, P. Pyle, and M. A. Patten (2020). "Eastern Screech-Owl (''Megascops asio'')", version 1.0. In ''Birds of the World''. P. G. Rodewald (Ed.). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> Various additional owl species known to be preyed upon by barred owls including the [[flammulated owl]] (''Psiloscops flammeolus''),<ref>Linkhart, B. D. and D. A. McCallum (2020). "Flammulated Owl (''Psiloscops flammeolus'')", version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.</ref> [[northern pygmy owl]] (''Glaucidium gnoma''),<ref name="Wiens" /> [[northern saw-whet owl]] (''Aegolius acadius'')<ref name= Graham /> and [[long-eared owl]] (''Asio otus'').<ref name="Bent" /> The interspecific owl trophic chain was perhaps most conspicuous in a case where a barred owl that was shot in New England was found to have a long-eared owl inside its stomach which in turn had an eastern screech-owl in its own stomach.<ref name="Voous" /><ref name="Bent" /> More unexpectedly, barred owls may even prey on other ''Strix'' species. As many as four records of circumstantial but likely predation by barred owls on [[spotted owl]]s have been reported.<ref name="Wiens" /> A likely event of predation by a barred owl on an adult [[great grey owl]] was observed. The authors hypothesized that the victim may have been a smaller male great grey owl (which can be about the same body mass as a large female barred) but this is the only known instance to date of a great gray owl being killed by another species of ''Strix'' owl.<ref>{{cite journal|doi=10.3356/0892-1016(2006)40[175:PPOGGO]2.0.CO;2|issn=0892-1016 |date=2006 |volume=40 |page=175 |title=Possible Predation of Great Gray Owl by a Barred Owl |last1=Graves |first1=Gary R. |last2=Niemi |first2=Gerald J. |journal=Journal of Raptor Research |issue=2 |s2cid=86070731 |doi-access=free }}</ref> Barred owls have been known to take adults (or full-grown juveniles) of diurnal raptors as well, including [[snail kite]]s, [[Cooper's hawk]]s, [[sharp-shinned hawk]]s and possibly [[swallow-tailed kite]]s.<ref name= Fisher /><ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/journals/jfo/v058n02/p0171-p0189.pdf|author=Sykes, P.W. Jr. |year=1987|title=Some aspects of the breeding biology of the Snail Kite in Florida|journal=J. Field Ornithol.|volume= 58|pages= 171–189|jstor=4513216}}</ref><ref>{{cite journal|author=Hertzel, A.X. |year=2003|title=Barred Owl takes Cooper's Hawk?|journal=Loon |volume=75|page=58}}</ref><ref>{{cite journal|doi=10.3356/JRR-07-08.1 |title=Predators of the Swallow-Tailed Kite in Southern Louisiana and Mississippi |date=2008 |last1=Coulson |first1=Jennifer O. |last2=Coulson |first2=Thomas D. |last3=Defrancesch |first3=Sherry A. |last4=Sherry |first4=Thomas W. |journal=Journal of Raptor Research |volume=42 |pages=1–12 |s2cid=84286796 |doi-access=free }}</ref>

== Reproduction ==
[[File:Two-owls-perched-branch - West Virginia - ForestWander.jpg|thumb|right|A probable mated pair of barred owl adults in daytime]]

The barred owl's preferred nest site is usually the [[Tree hollow|hollow trunk]] of a large tree or the broken-off [[Snag (ecology)|snag]] from a large tree branch. Hollows or snags may be made by any variety of sources, often due to a [[Plant pathology|disease]] or storm, with hollows and snags large enough to accommodate these birds usually only occurring in an old-growth tree.<ref name= Hume /><ref name= Bent /><ref name= Peck /><ref name= Devereux /> Typically, nest sites are in rather deep and dark wooded areas, often with a well-developed understory but somewhat sparse lower branches, and may be fairly close to water.<ref name= Konig /><ref name= Applegate /> Average nest heights are between {{convert|6.8|and|13.4|m|ft|abbr=on}} above the ground.<ref name= BNA /> In 25 studies from throughout the range, mean nest tree height was {{convert|18.2|m|ft|abbr=on}} (lowest mean from Florida where it was {{convert|5.9|m|ft|abbr=on}}; the highest from Oregon where it was {{convert|28|m|ft|abbr=on}}), mean nest tree diameter was {{convert|65.7|cm|in|abbr=on}} (thinnest mean in Saskatchewan at {{convert|47.4|cm|in|abbr=on}}; thickest in Washington at {{convert|106|cm|in|abbr=on}}), while the mean height of the tree cavity used from these studies was {{convert|9.8|m|ft|abbr=on}}.<ref name= Livezey5 />

A big [[beech]] with a rotting core, encompassing a large cavity reached through a deep crevice, is an ideal nest site.<ref name= Hume /> The most widely reported nesting trees in breeding cards were [[elm]]s (21%) and beeches (15%), followed by [[oak]]s, [[Hickory|hickories]], [[Betula alleghaniensis|yellow birches]], [[Platanus occidentalis|sycamores]], [[aspen]]s, [[maple]]s and [[Populus|poplars]].<ref name= Apfelbaum>{{cite journal|url=https://biostor.org/reference/216633|author1=Apfelbaum, S. I. |author2= Seelbach, P. |year=1983|title=Nest Tree, Habitat Selection and Productivity of Seven North American Raptor Species Based on the Cornell University Nest Record Card Program|journal= Raptor Research|volume= 17|issue=4|pages=97–113}}</ref> In Washington, the most often used nest trees were [[Populus balsamifera|balsam poplar]], [[Pseudotsuga menziesii|Douglas fir]] and [[Abies grandis|grand fir]].<ref name="Buchanan" /> Balsam poplar comprised 62% of known nest sites in Manitoba as well.<ref name="Whiklo2" /> It was found in Maryland that snags used were significantly higher than the average height of miscellaneous snags available in environment. The mean size of tree holes the owls used in Maryland was {{convert|33|cm|in|abbr=on}} in inside diameter and {{convert|54|cm|in|abbr=on}} in depth.<ref name="Devereux" /> These were slightly larger than the average from Michigan, which hollow used averaged {{convert|25|cm|in|abbr=on}} in mean diameter and {{convert|35|cm|in|abbr=on}} in mean depth.<ref name="Postupalsky" /> Record depth tree cavities used by barred owls was around {{convert|2.4|m|ft|abbr=on}} deep from the opening on the tree.<ref name="Bent" /> One study of cavity nesting birds in Ontario found that the barred owl preferred to nest in the most massive trees of any cavity-nester in the study area.<ref>James, R. D. (1984). [https://docs.ontario.ca/documents/2793/guide-cavity.pdf ''Habitat management guidelines for cavity-nesting birds in Ontario'']. Ontario ministry of natural resources.</ref> In continuous bottomland forest, nests are often about every {{convert|226|ha|acre|abbr=on}}.<ref>{{cite journal|jstor=4159308|author=Bell, R. E. |year=1964|title=A sound-triangulation method for counting Barred Owls|journal=The Wilson Bulletin|volume=76|issue=3|pages= 292–294}}</ref> Territory lines often remain the same even after the original owls are replaced entirely by a new pair.<ref name= Nicholls /> It was thought in Nova Scotia that some pairs may prospect a potential nest site as much as year before they use it.<ref name= Elderkin /> Despite usually using sickly or dying trees, some nests have found in partially hollow but still living [[oak]]s.<ref name= Konig />

[[File:Barred-owl-chick-17b.jpg|thumb|left|Barred owl nestlings peer out of the typical nesting site, a spacious tree hollow]]

Usually in areas with few or no natural tree hollows, often within younger [[secondary forest]]s or [[Overexploitation|overharvested]] areas, this species will uses other [[Nest|birds' nests]] and occasionally also the [[drey]]s of squirrels.<ref name= Konig /><ref name= Hume /><ref name= Apfelbaum /> Evidence shows that the preference of barred owls for hollows and snags over bird nests is due to their earlier nest type having a more secure [[microclimate]] with better shelter (additionally, owl nests in hollows generally tend to be somewhat less vulnerable to predation than those of owls using old bird nests).<ref name= Bent /><ref>{{cite journal|author1=McComb, W. C.|author2= Noble, R. E. |year=1981|title=Microclimates of nest boxes and natural cavities in bottomland hardwoods|journal= The Journal of Wildlife Management|volume= 45|issue=1|pages=284–289|doi= 10.2307/3807906 |jstor= 3807906 }}</ref> Nest built by other birds that are most widely used are probably [[red-shouldered hawk]] and [[Cooper's hawk]]s, while those of [[red-tailed hawk]]s, usually being in more open areas, are used secondarily outside of a local basis.<ref name= Voous /><ref name= Shupe /><ref>{{cite book  | last = Sattler | first = Helen Roney  | author-link = Helen Roney Sattler  | title = The Book of North American Owls  | publisher = Clarion Books  | year = 1995  | page = 41  | url = https://archive.org/details/bookofnorthameri0000satt/page/41| url-access = registration | isbn = 0-395-60524-5}}</ref> In the south, nests have been found between fronds of [[Sabal|palmetto]] palm leaves, in holes of broken palm stems and [[Snag (ecology)|rotten snags]] of the palms.<ref name= Konig /> One unconventional nest was on the ground at the base of a lookout tower in [[Everglades National Park]].<ref name= Robertson>{{cite journal|author=Robertson, W. B. |year=1959|title=Barred Owl nesting on the ground|journal= The Auk|volume= 76|issue=2|pages=227–230|doi=10.2307/4081780 |jstor=4081780 |doi-access=free}}</ref> Another was on the roof of a shed in Saskatchewan.<ref>{{cite journal|author1=Houston, C. S. |year=1999|title=Barred Owl nest in attic of shed|journal= Wilson Bulletin |volume=111 |issue=2|pages=272–273}}</ref> Yet another was in an [[Bank (geography)|earthen bank]] in Texas.<ref>{{cite journal|author1=Shackelford, C. E. |year=1996|title=Barred Owl nest in a natural hole in an earthen bank in eastern Texas|journal= J. Raptor Res. |volume=30 |issue=1|page=41}}</ref> Locally, barred owls can take to [[nest box]]es but, in general, barred owls take to these less readily than their cousin ''Strix'' owls in Europe.<ref name= Konig /><ref>{{cite journal|author1=Johnson, D. H.|author2= Follen, D. G. |year=1984|title=Barred Owls and nest boxes|journal= Raptor Res|volume= 18|issue=1|pages=34–35|url=https://sora.unm.edu/sites/default/files/journals/jrr/v018n01/p00034-p00035.pdf}}</ref> Suitable nesting hollows may be used quite often in subsequent years, with records of a single hollow seeing up to 25 years of barred owl use (presumably not by the same owls however).<ref name= Konig /> Other long-used nests were one reused in New England for 10 years by the same pair until it rotted out and while a nest box in Nova Scotia was reused 10 times over 16 years.<ref name= Bent /><ref name= Elderkin /> Over 6 years in Minnesota, 14 nest boxes were reused; 7 were used once, 6 were twice and one was used three times.<ref name= Johnson2>Johnson, D. H. (1987). "Barred Owls and Nest Boxes-Results of a Five-Year Study In Minnesota". In ''Biology and Conservation of Northern Forest Owls: Symposium Proceedings'': February 3–7, 1987, Winnipeg, Manitoba (Vol. 142, No. 3, p. 128). Fort Collins, Colo.: Rocky Mountain Forest and Range Experiment Station.</ref> Like all owls, barred owls never construct their owl nest but they may press or dig slightly if soil is present or remove the top leaves from a squirrel [[drey]].<ref name= Bent /><ref name= Elderkin />

In normal circumstances, barred owls tend to pair bond for life.<ref name= BNA /> Courting pairs are usually newly mature birds but also possibly widowed owls or those re-establishing existing pair bonds after the winter.<ref name= BNA /><ref name= Bent /> During courtship, barred owl males especially may engage in nodding, bowing with half-spread wings and may wobble and twist their head from side to side.<ref name= BNA /><ref name= Bent /> Courting pairs will often engage in duets.<ref>{{Cite web |title=Barred Owl {{!}} Audubon Field Guide |url=https://www.audubon.org/field-guide/bird/barred-owl |access-date=2023-12-14 |website=www.audubon.org |language=en}}</ref> [[Copulation (zoology)|Copulation]] between pairs usually occurs in late winter, February to March, and occurs several times, probably to ensure implantation.<ref>{{cite journal|url=https://sora.unm.edu/sites/default/files/154-164%20notes%20OB%20Vol%2022%233%20Dec%202004.pdf|author=Robinson, C. |year=2004|title=Barred Owl Mating Behaviour|journal= Ontario Birds|volume=22 |issue=3|pages=154–156}}</ref> The female enters a pre-breeding lethargy stage wherein she is fed by the male.<ref name= Elderkin /> In barred owls, egg laying occurs at two to three day intervals.<ref name= Hume /> Egg laying typically begins in March and runs throughout April. In more tropical locales like Florida, egg laying may occur as early as late December, though 22 were laid in between early January and early March. At similar latitudes in Texas, 22 first eggs were laid between as early as mid-February to as late as early June (although the latter may have been a replacement clutch).<ref name= BNA /> 23 clutches in Iowa and Illinois were initiated in between late February and late April, with roughly corresponding initial egg dates in New Jersey and probably western Maryland as well.<ref name= BNA /><ref name= Bosakowski /><ref name= Devereux /> 63 initial eggs in New England were laid between mid-March and mid-May.<ref name= Bent /> Further north, 38 clutches in Nova Scotia were initiated in between late March and late May, with initial clutches dates about a week later in Ontario.<ref name= Peck /><ref name= Elderkin /> Normally the female lays 2 to 3 eggs, although as many as 5 is possible, directly on the base of the nest site.<ref name= Konig /> The mean clutch size in three broad samples from several parts of the range was between 2.22 and 2.46.<ref name= Bent /><ref name= Apfelbaum /><ref>{{cite journal|author=Murray, G. A. |year=1976|title=Geographic variation in the clutch size of seven owl species|journal= Auk |volume=93|issue=3 |pages= 602–613|jstor=4084960}}</ref> In Minnesota, the mean clutch size was 2.68.<ref name= Johnson2 /> The eggs are pure white, slightly rough and not glossy, and oval in shape.<ref name= BNA /> In 157 eggs, the length of the egg could measure from {{convert|42.5|to|55.5|mm|in|abbr=on}} while the diameter could range from {{convert|37.5|to|45.3|mm|in|abbr=on}}, with a mean of {{convert|50.6|×|43.3|mm|in|abbr=on}}.<ref name= Bent /> 25 eggs in Nova Scotia averaged slightly smaller, at {{convert|49|x|41|mm|in|abbr=on}}.<ref name= Elderkin /> The mean weight of the egg is around {{convert|45.5|g|oz|abbr=on}}.<ref name= Elderkin /> The female alone incubates, doing so for about 28 days, while the male gathers food for her.<ref name= Konig />

The female tends to closely brood the young for three weeks. Then after, she begins to hunt for the young. Both parents normally continue hunt for the young until they are about 6 weeks old and can fly well.<ref name= Hume /> During the first three weeks, the male does all prey deliveries, either bringing prey directly into the nest or leaves for the female at the nest entrance or on a nearby branch. The mean number of prey deliveries when the young are 6–10 days old is 2.4 per night, 1.4 when they are 11–15 days old, 3.6 when they are 16–20 days old and 2.2 when they are 21–25 days old. He will continue hunting until the young disperse.<ref name= BNA /><ref name= Elderkin /><ref name= Robertson /> The female's prey deliveries are much more frequent when she resumes hunting, ranging from a mean of 4.8 to 8 deliveries nightly.<ref name= BNA /><ref name= Elderkin /> Male prey deliveries are often sporadically at any point through the night while female deliveries tend to be clustered immediately after sunset or just before sunrise.<ref name= Elderkin /> Barred owls have a variable reaction to human disturbance. Some parent owls remain sitting, while some leave the nest upon a person's approach and some attack people climbing to the nest, as well as those approaching young on or near the ground.<ref name= Bent /><ref name= Dunstan /><ref name= Henderson>{{cite journal|author=Henderson, G. |year=1933|title=Boldness of Barred Owls when danger threatens young|journal= Wilson Bulletin |volume=45|page=143|url=https://sora.unm.edu/sites/default/files/journals/wilson/v045n03/p0143-p0143.pdf}}</ref> There are several accounts of barred owls engaging in fierce nest defense against humans, sometimes reportedly knocking people out of trees.<ref name= Voous /><ref name= Bent /><ref name= Henderson /> However, their aggression is variable and, based on studies of similar owls like tawny and Ural owls from Europe, attacks tend to only occur when intrusions and disturbance by humans are frequent. A distraction display was recorded by a female barred owl when humans approached. In it, she spread and quivered her wings and engaged in chittering and squealing, somewhat similar to the sounds made by begging young.<ref>{{cite journal|url=https://sora.unm.edu/node/137289|author1=Bird, D.M. |author2=Wright, J.O. |year=1977|title=Apparent distraction display by a Barred Owl|journal=Canadian Field-Naturalist |volume=91|issue=2 |pages= 176–177|doi=10.5962/p.345368 |doi-access=free}}</ref>

[[File:Barred-owl-chick-58.jpg|thumb|A chick nuzzles its mother after leaving its nest]]

The average hatchling weighs about {{convert|46|g|oz|abbr=on}}.<ref name= Bent /><ref name= Elderkin /> Like most birds, the young are initially [[Altriciality|altricial]]. The white [[Down (feather)|down]] feathers that the barred owls are hatched with is replaced by white-tipped barred-buff second down at two to three weeks of age, correspondingly with growth of the wing primaries.<ref name= BNA /> The earlier chicks are bigger and stronger, while the latter ones may not survive if food is scarce.<ref name= Hume /> Size differences between barred owl nestlings may be less pronounced if the female does not begin incubation until the laying of the second egg.<ref name= BNA /> The larger young may fight with the younger siblings for food.<ref name= Hume /> The young barred owls first start moving about the nest at around this 3 week point and may start to perform threat displays if scared.<ref name= BNA /><ref name= Varchmin>Varchmin, T. E. M. (1977). ''The Behavioral and Physical Development of Barred Owl (Strix Varia) Nestlings in Illinois'' (Doctoral dissertation, Western Illinois University).</ref> Adult-like feathers begin to appear at six weeks of age, starting at the scapulars, then radiating down across the abdomen and flanks up through the upper breast, with the last wisps of down remaining for up to 4 months.<ref name= BNA /><ref name= Bent /><ref name= Varchmin /> The young often start exploring around the nest tree, often falling to ground, which makes them quite vulnerable to predation despite the parents' continued protection. However, the fledglings can usually clamber back up the tree using their feet and bills, constantly wing-flapping.<ref name= Elderkin />

Fledging occurs at about 36–39 days.<ref name= Voous /> After that, both parents continue to hunt for the young but prey deliveries taper off as the young begin to make their first flights and practice hunting.<ref name= Hume /><ref name= Dunstan /><ref name= Varchmin /><ref>[http://www.smm.org/warnernaturecenter/animals/owl/ ''Barred Owl Factsheet''] {{Webarchive|url=https://web.archive.org/web/20150428114551/http://www.smm.org/warnernaturecenter/animals/owl/ |date=2015-04-28 }}, Lee and Rose Warner Nature Center, 2008</ref> Short flights are typical when the young barred owls are up to around 10 weeks old with longer flights commencing at about 14 weeks.<ref name= Varchmin /> By the time they are flying and hunting somewhat assuredly in early to mid-autumn, the young move away and gain independence.<ref name= Hume /><ref name= Johnsgard /> Dispersal of 5 young from Nova Scotia was {{convert|0.8|to|64|km|mi|abbr=on}} away from their nests of origin. Furthermore, a recovered 6 month old was {{convert|8|km|mi|abbr=on}} away from its nest of origin, while five encountered as adults were found at a distance of {{convert|16|and|43|km|mi|abbr=on}} from the nests where they hatched. An exceptional dispersal distance from Nova Scotia was {{convert|1600|km|mi|abbr=on}} away to [[Stoney Creek, Ontario]].<ref name= Elderkin /> The post-dispersal stage is one of great mortality among young owls.<ref name= Hume /> Usually juvenile owls are considered "floaters", often hovering around the perimeter of fiercely defended territories for some time. In some areas, floaters may make use of nest boxes more readily than mature birds.<ref name= Nicholls /><ref name= Elderkin /> Yearlings have been known to breed only very rarely, otherwise barred owl usually first breed when they are around two (sometimes three) years old. Therefore, around two years old is considered the age of maturity.<ref name= BNA /><ref name= Hybridization>{{cite journal|doi=10.2307/4088616|url=https://sora.unm.edu/sites/default/files/journals/auk/v111n02/p0487-p0492.pdf|title=Hybridization Between Barred and Spotted Owls|journal=The Auk|date=April 1994 |volume=111|issue=2|pages=487–492|author1=Hamer, Thomas E. |author2=Forsman, Eric D.|jstor=4088616 }}</ref> The percentages of successful nests (i.e. at least 1 fledgling produced per attempt), per study were found to be: 86% of 22 clutches in Minnesota (with a mean of 2.42 fledglings per successful attempt),<ref name= Johnson2 /> 66% of 114 clutches in Michigan (with a mean of 1.97 fledglings per successful attempt),<ref name= Postupalsky /> 25% of 6 clutches in Maryland (with a mean of 1 fledgling per all attempts and 1.48 per successful attempts),<ref name= Devereux /> 69% of 48 clutches in Nova Scotia (with a mean of 0.25 fledgling per all attempts and 2 per successful attempts)<ref name= Elderkin /> and 50% of 12 nests in Washington state. Little is known about the specific factors that dictate breeding success, but are likely to include the quality of the nesting site, the food supply in the area, the levels of disturbance from outside actors (usually humans) and the maturity of the pair.

== Longevity and parasitism ==
The barred owl is a naturally long-living bird. Some record lifespans recorded per banding studies in the wild are 18 years 2 months (initial banding [[Kentucky]], died in [[Ohio]]) and 24 years and 1 month in Minnesota.<ref>{{cite journal|author1=Klimkiewicz, M. K.|author2= Futcher, A. G. |year=1987|title=Longevity Records of North American Birds: Coerebinae through Estrildidae|jstor=4513247|journal=Journal of Field Ornithology|pages= 318–333|url=https://sora.unm.edu/sites/default/files/journals/jfo/v058n03/p0318-p0333.pdf|volume=58|issue=3}}</ref><ref name= Orfinger>{{cite journal|title=Longevity of the Barred Owl (''Strix varia'' Barton, 1799) from captivity|date=2018 |doi=10.1676/1559-4491.130.4.1009 |last1=Orfinger |first1=Alexander B. |last2=Helsel |first2=Debbie |last3=Breeding |first3=Shawnlei F. |journal=The Wilson Journal of Ornithology |volume=130 |issue=4 |page=1009 |s2cid=196672746 }}</ref> There are several records of breeding barred owls nesting successfully for a decade or more.<ref name= BNA /><ref name= Johnsgard /> The record lifespan for a barred owl in captivity, where many animals can live longer without the stresses of surviving in wild conditions, was 34 years and 1 month, with six records of captive barred owls living over 30 years.<ref name= Orfinger /> Known causes of mortality are diverse, some due to predation (largely great horned owls, for nestlings to adults, and probably raccoons, for eggs, nestlings and fledglings).<ref name= BNA /><ref name= Johnsgard /> Some mortality is known to occur during hunting accidents.<ref name= BNA /> There are cases of barred owls being inadvertently killed in [[Trapping|furbearer traps]].<ref>{{cite journal|jstor=3782498|author1=Stocek, R. F.|author2=Cartwright, D. J. |year=1985|title=Birds as nontarget catches in the New Brunswick furbearer harvest|journal=Wildlife Society Bulletin|volume= 13|issue=3|pages= 314–317}}</ref> Sometimes deaths occurs due to the defenses of prey.<ref name= Voous /> One barred owl was killed by the bite of an unknown rodent that was likely defending itself.<ref>{{cite journal|author1=Gibson, M. J.|author2=Gibson, D. C.|author3= Bardelmeier, D. G. |year=1998|title=Prey conquers predator: A case study-Barred owl dies from rodent-inflicted wound|journal= Journal of Wildlife Rehabilitation|volume= 21|issue=3–4|pages= 19–21}}</ref> Some cases of [[cannibalism]] between adult barred owls have been reported as well.<ref>Lloyd, J. (2016). [https://open.pubpub.org/pub/cannibalism-by-a-barred-owl/release/3 ''Cannibalism by a Barred Owl'']. Open.</ref> This species, like other forest owls, is vulnerable to the respiratory disease [[aspergillosis]].<ref>Hunter, D. B., McKeever, K., McKeever, L., & Crawshaw, G. (1987). "Disease susceptibility in owls". In: ''Biology and conservation of northern forest owls''. RW Nero, RJ Clark, RJ Knapton, and RH Hamre (Eds). USDA, Forest Service General Technical Report RM-142. Fort Collins, Colorado, USA, 67–70.</ref> Spontaneous infections of [[West Nile fever]] are also known to kill wild barred owls.<ref>{{cite journal|title=Clinical findings, lesions, and viral antigen distribution in great gray owls (''Strix nebulosa'') and barred owls (''Strix varia'') with spontaneous West Nile virus infection|date=2007 |volume=51 |pmid=17461282 |doi=10.1637/0005-2086(2007)051[0140:CFLAVA]2.0.CO;2|issn=0005-2086 |last1=Lopes |first1=Hugo |last2=Redig |first2=Pat |last3=Glaser |first3=Amy |last4=Armien |first4=Anibal |last5=Wünschmann |first5=Arno |journal=Avian Diseases |issue=1 |pages=140–145 |s2cid=34386856 }}</ref> Barred owls were the most regularly infected with West Nile Virus of owl species in Georgia, as about 15% of studied barred tested positive (still at a lower rate than some hawks).<ref>{{cite journal|pmid=17495305 |doi= 10.7589/0090-3558-43.2.214|title= Pathology and Epidemiology of Natural West Nile Viral Infection of Raptors in Georgia|date= 2007|last1= Ellis|first1= Angela E.|last2= Mead|first2= Daniel G.|last3= Allison|first3= Andrew B.|last4= Stallknecht|first4= David E.|last5= Howerth|first5= Elizabeth W.|journal= Journal of Wildlife Diseases|volume= 43|issue= 2|pages= 214–223|s2cid= 10160266|doi-access= free}}</ref> Cases of [[Avipoxvirus]] are also known in barred owls but, as with West Nile virus, the rate of mortality to viral infection is not well-known.<ref>{{cite journal|pmid=9131568 |doi=10.7589/0090-3558-33.2.323 |title=Avian Pox in Eastern Screech Owls and Barred Owls from Florida |date=1997 |last1=Deem |first1=Sharon L. |last2=Heard |first2=Darryl J. |last3=Fox |first3=Jonathan H. |journal=Journal of Wildlife Diseases |volume=33 |issue=2 |pages=323–327 |s2cid=27579503 }}</ref> A case of [[follicular thyroid cancer]] was found in a wild barred owl that was unable to continue to fly.<ref>{{cite journal|title=Productive thyroid follicular carcinoma in a wild barred owl (''Strix varia'')|date=2012 |pmid=23051831 |doi=10.1177/1040638712463562 |last1=Brandão |first1=João |last2=Manickam |first2=Bala |last3=Blas-Machado |first3=Uriel |last4=Cohen |first4=Eli |last5=Mejia-Fava |first5=Johanna |last6=Divers |first6=Stephen |last7=Mayer |first7=Jörg |journal=Journal of Veterinary Diagnostic Investigation |volume=24 |issue=6 |pages=1145–1150 |s2cid=24254967 |doi-access=free }}</ref> [[Fatty liver disease]]s have been recorded for barred owls in captivity.<ref>{{cite journal|title=Diagnosis and treatment of hepatic lipidosis in a barred owl (''Strix varia'')|date=2000 |volume=14 |page=268 |doi=10.1647/1082-6742(2000)014[0268:DATOHL]2.0.CO;2|issn=1082-6742 |last1=James |first1=Stephanie B. |last2=Raphael |first2=Bonnie L. |last3=Clippinger |first3=Tracy |journal=Journal of Avian Medicine and Surgery |issue=4 |s2cid=86350310 }}</ref> [[Eye injury|Eye lesions]] are fairly common in barred owls, but can be survived and possibly [[Surgery|surgically]] corrected.<ref>{{cite journal|pmid=6605960|title=Surgical correction of a luxated cataractous lens in a barred owl| journal=Journal of the American Veterinary Medical Association | date=1983 | last1=Brooks | first1=D. E. | last2=Murphy | first2=C. J. | last3=Quesenberry | first3=K. E. | last4=Walsh | first4=M. T. | volume=183 | issue=11 | pages=1298–1299 }}</ref>

[[File:Barred Owl with Fishing Line (8158631483).jpg|thumb|left|A barred owl that drowned after entanglement with fishing line]]

[[Parasitism]] is frequent in barred owls as expected for many different kinds of wild birds.<ref>{{cite journal|author1=Herman, C. M. |year=1944|title=The blood protozoa of North American birds|journal=Bird-banding|volume=15|issue=3|pages=89–112|doi=10.2307/4509831 |jstor=4509831 }}</ref> The parasite load of [[helminth]]s was determined to be higher in larger owls in Florida like the barred and great horned owl and lower in smaller owl species, like [[eastern screech owl]].<ref>{{cite journal|author1=Kinsella, J. M.|year=2001|title=Parasitic helminths of five species of owls from Florida, USA|journal=Comparative Parasitology|volume=68|issue=1|pages=130–133}}</ref> While parasitic infestations are not typically detected as direct mortality causes, in some severe cases complications or direct death can occur. These cases of mortality are most widely recorded in cases of [[toxoplasmosis]], although generally owls have lower rates of dangerous ''[[Toxoplasma]]'' parasites than some other species of birds of prey.<ref>{{cite journal|title=Severe hepatitis resulting from toxoplasmosis in a barred owl (''Strix varia'') from Québec, Canada|date=1997 |pmid=9356724|doi=10.2307/1592169|jstor=1592169 |last1=Mikaelian |first1=I. |last2=Dubey |first2=J. P. |last3=Martineau |first3=D. |journal=Avian Diseases |volume=41 |issue=3 |pages=738–740 }}</ref><ref>{{cite journal|author1=Niedringhaus, K. D.|year=2019|title=Trichomonosis due to ''Trichomonas gallinae'' infection in barn owls (''Tyto alba'') and barred owls (''Strix varia'') from the eastern United States|journal=Veterinary Parasitology: Regional Studies and Reports|volume=16|article-number=100281|doi=10.1016/j.vprsr.2019.100281 |pmid=31027606 |s2cid=92499182 }}</ref> Of barred owls in one study, 26.7% had ''[[Toxoplasma gondii]]'', the cause of toxoplasmosis, upon necropsy study, with adults having it more often than immature birds.<ref>{{cite journal|author1=Lindsay, D. S.|year=1993|title=Prevalence of encysted ''Toxoplasma gondii'' in raptors from Alabama|journal=The Journal of Parasitology|volume=79 |issue=6 |pages=870–873|doi=10.2307/3283724 |jstor=3283724 |pmid=8277379 }}</ref> Lethal cases of [[trichomoniasis]] are also known.<ref>{{cite journal|author1=Pokras, M. A.|year=1993|title=Trichomoniasis in owls: report on a number of clinical cases and a survey of the literature|journal=Raptor Biomedicine|pages=88–91}}</ref> The effect of other parasites are more poorly known beyond generally compromising their hosts' condition, but in one case ''[[Sarcocystis strixi]]'' may have caused [[paralysis]] in a barred owl.<ref>{{cite journal|vauthors=Verma SK, Von Dohlen AR, Mowery JD, Scott D, Cerqueira-Cézar CK, Rosenthal BM, Dubey JP, Lindsay DS |year=2017|title=''Sarcocystis strixi'' n. sp. from a Barred Owl (''Strix varia'') Definitive Host and Interferon Gamma Gene Knockout Mice as Experimental Intermediate Host|journal=Journal of Parasitology|volume=103|issue=6|pages=768–777|pmid=28783438|doi=10.1645/16-173|hdl=10919/97335 |s2cid=20742726 |hdl-access=free}}</ref> Other parasites recorded in barred owls include ''[[Eimeria]] varia'',<ref>{{cite journal|vauthors=Upton SJ, Campbell TW, Weigel M, McKown RD|year=1990|title=The Eimeriidae (Apicomplexa) of raptors: review of the literature and description of new species of the genera ''Caryospora'' and ''Eimeria''|journal=Canadian Journal of Zoology|volume=68|issue=6|pages=1256–1265|doi=10.1139/z90-187}}</ref> ''[[Novyella]]'',<ref>{{cite journal|vauthors=Telford SR Jr, Forrester DJ|year=1992|title=Morphological comparisons of the ''Plasmodium'' (''Novyella'') species reported from North American birds, with comments on a species from the barred owl ''Strix varia'' Barton|journal=Systematic Parasitology|volume=22|issue=1|pages=17–24|doi=10.1007/BF00009632|s2cid=22795312 }}</ref> ''[[Diplostomidae|Neodiplostomum]]''<ref>{{cite journal|author1=Little, J. W.|author2= Hopkins, S. H. |year=1939|title=Trematodes from the barred owl, ''Strix varia''. Texas: Brachylaima mcintoshi|journal=Harkema|pages= 154–156}}</ref> as well as apparently rare species of ''[[Centrorhynchidae|Centrorhynchus]]'' and ''[[Tetrameridae|Tetrameres]]'' that were first found within barred owls.<ref>{{cite journal|author1=Van Cleave, H. J.|author2=Pratt, E. M. |year=1940|title=A new species of the genus ''Centrorhynchus'' (Acanthocephala) from the barred owl|journal= The Journal of Parasitology|volume=26|issue=4|pages=  297–300|doi=10.2307/3272102 |jstor=3272102 |doi-access=free}}</ref><ref>{{cite journal|author1=Pence, D. B.|author2= Mollhagen, T.|author3= Forrester, D. J. |year=1975|title=''Tetrameres (Gynaecophila) strigiphila'' sp. n. from the Florida barred owl, ''Strix varia georgica'', with notes on the status of the subgenus ''Gynaecophila'' (Nematoda: Tetrameridae)|doi=10.2307/3279331|journal= The Journal of Parasitology|volume= 61|issue= 3|pages= 494–498|jstor= 3279331}}</ref> [[Trematoda|Trematode flatworms]] such as [[Strigeidae|strigeids]] as well as ''[[Tylodelphys]]'' and ''[[Brachylaima]]'' are found in intermediate volume in barred owls relative to other owls.<ref>{{cite journal|author1=Chandler, A. C.|author2=Rausch, R. |year=1947|title=A study of strigeids from owls in north central United States|journal= Transactions of the American Microscopical Society|volume=66|issue=3|pages=  283–292|doi=10.2307/3223396 |jstor=3223396 }}</ref><ref>Little, J. W. (1975). [https://ojs.library.okstate.edu/osu/index.php/OAS/article/view/4951 "Trematodes from the Barred Owl, ''Strix varia'' in Texas: ''Brachylaima mcintoshi'' Harkema, 1939, and ''Neodiplostomum reflexum'' Chandler and Rausch, 1947"]. In ''Proceedings of the Oklahoma Academy of Science'' (Vol. 55, pp. 154–156).</ref><ref>{{cite journal|author1=Shoop, W. L.|author2=Corkum, K. C. |year=1980|title=''Tylodelphys immer'' Dubois 1961 (Trematoda: Diplostomidae) from the barred owl, ''Strix varia'' in Louisiana|journal=Journal of Parasitology|volume= 66|issue=4|pages=701–702|doi=10.2307/3280545 |jstor=3280545 |pmid=7420256 |doi-access=free}}</ref> Invertebrates such as [[Hippoboscidae|hippoboscid flies]] and ''[[Mallophaga]]'' are known to infect barred owls as [[Parasitism|ectoparasites]] but seldom at severe levels.<ref name= BNA /><ref>{{cite journal|author1=Holt, J. A. |year=2005|url=https://digitalcommons.unl.edu/insectamundi/77/|title=New host records of chewing lice (Mallophaga) on birds in Florida III|journal=Insecta Mundi|volume= 19 |issue=3|page=186}}</ref> Concern was expressed that barred owls may compromise spotted owl populations with novel parasites.<ref>Lewicki, K. E. (2013). [https://api.mountainscholar.org/server/api/core/bitstreams/529308ff-daa6-470e-b899-26ea3977a689/content Haemosporidian parasites of barred owls (''Strix varia'') and northern spotted owls (''S. occidentalis caurina''): Investigating the effects of an invasive species on parasite transmission and community dynamics]. Doctoral dissertation, Colorado State University.</ref> However, studies of ''[[Haemoproteus]]'' in barred and spotted owls in northwestern California found that native parasites were finding a new host in barred owls and may have been transmitted from spotted to barred owls but that the barred owl acted as a poor parasite host and may have diluted the parasite levels in owl populations. Furthermore, there was no evidence found that barred owls were spreading parasites to spotted owls.<ref>{{cite journal|title=Effects of barred owl (''Strix varia'') range expansion on ''Haemoproteus'' parasite assemblage dynamics and transmission in barred and northern spotted owls (''Strix occidentalis caurina'')|date=2015 |doi=10.1007/s10530-014-0828-5 |last1=Lewicki |first1=Krista E. |last2=Huyvaert |first2=Kathryn P. |last3=Piaggio |first3=Antoinette J. |last4=Diller |first4=Lowell V. |last5=Franklin |first5=Alan B. |journal=Biological Invasions |volume=17 |issue=6 |pages=1713–1727 |bibcode=2015BiInv..17.1713L |s2cid=254283674 |url=https://digitalcommons.unl.edu/icwdm_usdanwrc/1706 |url-access=subscription }}</ref>

== Status ==
[[File:Barred Owl Skeleton.jpg|thumb|Barred owl skeleton ([[Museum of Osteology]])]]

The barred owl is one of the most common owls in North America.<ref name= Hume /> [[Partners in Flight]] estimates that the barred owl may number up to 3 million individuals globally, making it, perhaps, the second most numerous North American owl behind the [[great horned owl]] and perhaps slightly ahead of other commoner species like [[Barn-owl|barn owl]]s and [[northern saw-whet owl]]s.<ref name= AllAbout>{{cite web |url=https://www.allaboutbirds.org/guide/Barred_Owl/lifehistory |title=Barred Owl, Life History |author=The Cornell Lab of Ornithology |publisher=allaboutbirds}}</ref> It estimated that Canada in total holds about 10,000–50,000 pairs.<ref>{{cite journal|doi=10.1016/S0006-3207(97)00051-7 |title=Population status and recent trends in Canadian raptors: A review |date=1998 |last1=Kirk |first1=David A. |last2=Hyslop |first2=Colleen |journal=Biological Conservation |volume=83 |issue=1 |pages=91–118 |bibcode=1998BCons..83...91K }}</ref> [[The Maritimes|Canadian Maritimes]] had highest densities known, with 3600 pairs, being found in 80% of {{convert|10|km2|sqmi|abbr=on}} blocks totaling 377; this was a conspicuously higher density than that recorded in Ontario, where they were in 28% of 1824 study blocks.<ref name= Sauer>{{cite journal|doi=10.3996/nafa.79.0001 |title=The North American Breeding Bird Survey 1966–2011: Summary Analysis and Species Accounts |date=2013 |last1=Sauer |first1=John R. |last2=Link |first2=William A. |last3=Fallon |first3=Jane E. |last4=Pardieck |first4=Keith L. |last5=Ziolkowski |first5=David J. |journal=North American Fauna |volume=79 |pages=1–32 |url=https://digital.library.unt.edu/ark:/67531/metadc700932/ }}</ref> Iowa, Tennessee and Maryland had the highest densities of pairs apparently in the United States, being present from 39 to 47% of blocks.<ref name= Sauer /> Throughout the year, the mean number of sightings per route is 0.12 sightings while during [[Christmas Bird Count]]s (CBC), the mean in 0.25 per route.<ref name= Sauer /><ref>Sauer, J. R., Schwartz S., & Hoover, B. (1996). ''The Christmas Bird Count homepage. Version 95.1''. Patuxent Wildlife Research Center, Laurel, MD.</ref>

== Barred owl and northern spotted owl ==
[[File:Barred owl.jpg|thumb|left|[[Gatineau Park]], [[Gatineau]], [[Quebec]]]]

Barred owls are thought to be partly responsible for the recent decline of the [[northern spotted owl]], native to British Columbia, [[Washington (state)|Washington]], [[Oregon]], and [[California]].<ref>{{cite journal|author=Livezey, K.B.|year= 2005|title= Iverson (2004) on Spotted Owls and Barred Owls: comments on methods and conclusion|journal= Journal of Raptor Research |volume=39|pages=102–103|url=https://sora.unm.edu/node/54163}}</ref><ref>{{cite journal |author=Kelly, E.G. |author2=Forsman, E.D. |author3=Anthony, R.G. |title=Are Barred Owls displacing Spotted Owls?|journal=The Condor|volume=105|page=45|doi=10.1650/0010-5422(2003)105[45:ABODSO]2.0.CO;2|url=https://www.fws.gov/oregonfwo/species/data/northernspottedowl/BarredOwl/Documents/KellyEtAl2003.pdf|year=2003|s2cid=86547489 }}</ref> The 2011 Revised Recovery Plan for the Northern Spotted Owl states "Based on the best available scientific information, competition from the barred owl (''S. varia'') poses a significant and complex threat to the spotted owl."<ref>[https://www.fws.gov/sites/default/files/documents/NSO_RevisedRP_2011.pdf Revised Recovery Plan for the Northern Spotted Owl (''Strix occidentalis caurina'')]. U.S. Fish and Wildlife Service, Portland, Oregon. (2011) p. vi</ref> Northern spotted owls were thought to be already declining considerably before barred owls moved into their range, mostly in sync with large-scale logging operations and land development carried out by humans, with their problems now further exacerbated by the barred species's presence.<ref name= Buchanan/> There are ecological discrepancies between the species in areas of sympatry. While both species prefer old-growth forest areas, the spotted owls tend to live in significantly higher elevation areas in Washington's Cascade mountains, with nest sites averaging {{convert|966.2|m|ft|abbr=on}} [[meters above sea level]] against a mean of {{convert|54.1|m|ft|abbr=on}} for barred owls, in areas with more steep slopes.<ref>{{cite journal|author1=Pearson, R. R.|author2= Livezey, K. B. |year=2003|title=Distribution, numbers, and site characteristics of spotted owls and barred owls in the Cascade Mountains of Washington|url=https://biostor.org/reference/216275|journal= Journal of Raptor Research|volume= 37|issue=4|pages= 265–276}}</ref><ref>{{cite journal|author1=Buchanan, J.|author2= Fleming, T.|author3= Irwin, L. |year=2004|title=A comparison of Barred and Spotted Owl nest-site characteristics in the Eastern Cascade Mountains, Washington|url=https://biostor.org/reference/216328|journal=  Journal of Raptor Research|volume= 38|pages= 231–237}}</ref> The barred owls of the area additionally prefer wetter, more variable forest areas, down to [[riparian zone]]s with limited forested land, while the spotted tended to cluster in more homogeneous upland and ancient [[Pinophyta|coniferous forests]].<ref name= Herter>{{cite journal|author1=Herter, D. R.|author2= Hicks, L. L. |year=2000|title=Barred owl and spotted owl populations and habitat in the central Cascade Range of Washington|url=https://biostor.org/reference/216080|journal= Journal of Raptor Research|volume= 34|issue=4|pages= 279–286}}</ref> However, little is known on the feasibility or benefits of habitat maintenance that favors spotted over barred owls. Habitat management measures are hypothesized to be insufficient to mitigate the negative effect the barred owls are having.<ref>{{cite journal|author1=Livezey, K.B.|author2= Fleming, T.L. |year=2009|title=Effects of Barred Owls on Spotted Owls: The need for more than incidental detections and correlational analysis|journal=  Journal of Raptor Research|volume= 41|issue= 4 |pages= 319–325|doi= 10.3356/0892-1016(2007)41[319:EOBOOS]2.0.CO;2 |s2cid= 86757049 |doi-access= free}}</ref><ref>{{ Cite journal | issue = 6 | year = 2019 | volume = 83 | pages = 1281–1296 | last1 = Long | first1 = L. | last2 = Wolfe | first2 = J. |journal=Journal of Wildlife Management | url = https://www.fs.usda.gov/psw/publications/long/psw_2019_long001.pdf | s2cid = 201192768 | id = {{ S2CID | 221379957 }} | title = Review of the effects of barred owls on spotted owls | doi = 10.1002/jwmg.21715 | bibcode = 2019JWMan..83.1281L }}. This review cites Mangan, A. O. (2018) [https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/4q77fw91b Effects of habitat characteristics, weather and presence of Barred Owls (''Strix varia'') on occupancy dynamics and breeding propensity of Northern Spotted Owls (''S. occidentalis caurina'') in Mount Rainier National Park]. Master's thesis. Oregon State University {{ S2CID | 199893769 }}</ref> In areas where barred owls moved in within {{convert|0.8|km|mi|abbr=on}} of a spotted owl nest area, 39% of spotted owls disappeared and were not seen again, while in areas still free of barred owls (so spared from this interspecific pressure), 11% of spotted owls disappeared and were not found again.<ref name= Kelly />

[[File:Barred Owl (Audubon).jpg|thumb|[[John James Audubon|Audubon]]'s illustration of a barred owl attacking a [[squirrel]]]]
Since the 1960s, barred owls have been expanding their range westward from the eastern US and Canada.<ref>Gremel, S. [https://web.archive.org/web/20110613203450/http://www.nature.nps.gov/YearInReview/yir2000/pages/02_nps_science/02_03_gremel.html ''Barred Owl Displaces Northern Spotted Owl at Olympic'']. Natural Resources Year in Review, U.S. National Park System.</ref> While some authors have described the expansion of barred owls into the west as "natural",<ref>Monahan, W. B., & Hijmans, R. J. (2007). ''Distributional dynamics of invasion and hybridization by Strix spp. in western North America''. Ornithological Monographs, 55–66.</ref> others state that this is a mischaracterization, as there is little to suggest that the barred owls could have reached the spotted's range without the inadvertent aid of humans — increasing temperatures, wildfire suppression, and tree planting likely facilitated the range increase.<ref>{{cite journal|doi=10.1525/auk.2008.125.1.230 |title=Natural range expansion of Barred Owls? A critique of Monahan and Hijmans (2007) |date=2008 |last1=Livezey |first1=Kent B. |last2=Root |first2=Terry L. |last3=Gremel |first3=Scott A. |last4=Johnson |first4=Craig |journal=The Auk |volume=125 |pages=230–232 |s2cid=86273621 |doi-access=free }}</ref> When spotted owls and barred owls share the same area, the barred owls generally are more aggressive and out-compete the spotted owls, leading to decreased populations of the native owls.<ref>{{cite journal|url=http://www.specifysoftware.org/Informatics/bios/biostownpeterson/PR_CB_2003.pdf |title=Using Ecological-Niche Modeling to Predict Barred Owl Invasions with Implications for Spotted Owl Conservation |doi=10.1046/j.1523-1739.2003.02206.x |author=Peterson, A. Townsend |author2=Robins, C. Richard |name-list-style=amp|journal=Conservation Biology |pages=1161–1165 |volume=17 |issue=4 |year=2003 |bibcode=2003ConBi..17.1161P |s2cid=86528384 |archive-url=https://web.archive.org/web/20080627040936/http://www.specifysoftware.org/Informatics/bios/biostownpeterson/PR_CB_2003.pdf |archive-date=2008-06-27 }}</ref> The more aggressive response of barred owls to interspecific stimuli has been verified with experiments incorporating vocalization and owl dummies.<ref>Van Lanen, N. J. (2010). ''Out with the old and in with the new?: investigating competition between Barred Owls (Strix varia) and Northern Spotted Owls (Strix occidentalis caurina) in northwestern California with a playback experiment''. Doctoral dissertation, Colorado State University. {{hdl|10217/38187}}</ref><ref>{{cite journal|doi=10.1016/j.biocon.2011.05.011 |title=Who hits and hoots at whom? Potential for interference competition between barred and northern spotted owls |date=2011 |last1=Van Lanen |first1=Nicholas J. |last2=Franklin |first2=Alan B. |last3=Huyvaert |first3=Kathryn P. |last4=Reiser |first4=Raoul F. |last5=Carlson |first5=Peter C. |journal=Biological Conservation |volume=144 |issue=9 |pages=2194–2201 |bibcode=2011BCons.144.2194V |s2cid=53326444 |url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2330&context=icwdm_usdanwrc |url-access=subscription }}</ref> Additionally, the adult survival rates appear higher for barred owls (an estimated 91%) than for spotted owls (an estimated 82%). Therefore, the barred owl is considered "demographically superior".<ref name= Wiens /> In December 2023, the [[U.S. Fish and Wildlife Service]] issued a draft of a management plan indicating that hunters in the Pacific Northwest would be encouraged to shoot more than a half million barred owls. The rationale was to cull the numbers of this invasive species, to help protect native species, particularly the spotted owl which had been listed as threatened under the Endangered Species Act.<ref>{{cite web |url=https://www.newsweek.com/invasive-species-barred-owl-cull-pacific-northwest-1850348|title=US Government Wants Hunters to Shoot 500,000 Owls|date=December 7, 2023|work=Newsweek|access-date=December 10, 2023|quote=Barred owls are an invasive species in the Pacific Northwest, originating on the U.S. East Coast, and they pose a huge threat to native protected species, including northern spotted owls.}}</ref>

Another potential threat is that barred owls and spotted owls occasionally interbreed, creating hybrids ("sparred owl" or "botted owl").<ref name= Hybridization /><ref>[https://web.archive.org/web/20021228024241/http://news.nationalgeographic.com/news/2002/12/1217_021226_tvinterbreeding.html ''Interbreeding Threatens Rare Species, Experts Claim''], Guynup, Sharon, National Geographic</ref> Only 47 hybrids with barred owls (all between female barred owls and male spotted owls) were found in an analysis of more than 9,000 banded spotted owls; consequently, hybridization between these two species is considered to be "an interesting biological phenomenon that is probably inconsequential compared with the real threat—direct competition between the two species for food and space".<ref name= Hybridization /><ref name="Kelly&Forsman2004">{{cite journal|vauthors=Kelly EG, Forsman ED|year= 2004|title= Recent records of hybridization between barred owls (''Strix varia'') and northern spotted owls (''S. occidentalis caurina'')|journal= Auk |doi=10.1642/0004-8038(2004)121[0806:RROHBB]2.0.CO;2|volume=121|issue= 3|pages=806–810|s2cid= 86769738}}</ref><ref>{{cite journal|url=https://sora.unm.edu/node/122898|author1=Seamans, M. E.|author2= Corcoran, J.|author3= Rex, A. |year=2004|title=Southernmost record of a spotted owl × barred owl hybrid in the Sierra Nevada|journal=Western Birds|volume= 35|pages= 173–174}}</ref> Most hybrids favor their barred owl heritage with similar and more pale overall coloring than spotted owls, though the back tends to be intermediate in color between the two and the beak coloring is variable. However, there has been much variation described.<ref name= BNA /><ref name= Hybridization /> Due to variances in appearance, previously hybrids between the species were overestimated from field identification, only being certainly identified by genetic [[Locus (genetics)|loci]].<ref>{{cite journal|title=Microsatellite loci for distinguishing spotted owls (''Strix occidentalis''), barred owls (''Strix varia''), and their hybrids|date=2007 |doi=10.1111/j.1471-8286.2006.01581.x |last1=Funk |first1=W. Chris |last2=Mullins |first2=Thomas D. |last3=Forsman |first3=Eric D. |last4=Haig |first4=Susan M. |journal=Molecular Ecology Notes |volume=7 |issue=2 |pages=284–286 |url=https://digitalcommons.unl.edu/usgsstaffpub/687 |url-access=subscription }}</ref><ref>{{cite journal|doi=10.1111/j.1523-1739.2004.00206.x |title=Genetic Identification of Spotted Owls, Barred Owls, and Their Hybrids: Legal Implications of Hybrid Identity |date=2004 |last1=Haig |first1=Susan M. |last2=Mullins |first2=Thomas D. |last3=Forsman |first3=Eric D. |last4=Trail |first4=Pepper W. |last5=Wennerberg |first5=LIV |journal=Conservation Biology |volume=18 |issue=5 |pages=1347–1357 |bibcode=2004ConBi..18.1347H |s2cid=43989899 |url=https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1679&context=usgsstaffpub |url-access=subscription }}</ref> Moreover, no recent hybrids could be detected in a survey of the [[Cascade Mountains]].<ref name= Herter /><ref>{{cite journal|doi=10.1534/g3.118.200754|title=Whole-Genome Analysis of Introgression Between the Spotted Owl and Barred Owl (''Strix occidentalis'' and ''Strix varia'', Respectively; Aves: Strigidae) in Western North America|date=2018 |last1=Hanna |first1=Zachary R. |last2=Dumbacher |first2=John P. |last3=Bowie |first3=Rauri C K. |last4=Henderson |first4=James B. |last5=Wall |first5=Jeffrey D. |journal=G3: Genes, Genomes, Genetics |volume=8 |issue=12 |pages=3945–3952 |pmid=30355766 |pmc=6288836 }}</ref><ref>Hanna, Z. R. (2017). [https://escholarship.org/uc/item/2nh1474g Genomics of the Spotted Owl (''Strix occidentalis'') and Barred Owl (''Strix varia'') in Western North America]. Doctoral dissertation, UC Berkeley.</ref>

== In art ==
[[John James Audubon]] illustrated the barred owl in ''[[Birds of America (book)|Birds of America]]'' (published in London, 1827–1838) as Plate 46, where it is shown threatening a [[eastern gray squirrel|grey squirrel]]. The image was engraved and colored by [[Robert Havell]]'s London workshops. The original [[aquatint]] by Audubon is owned by the Brooklyn Museum.<ref name="Brooklyn Museum">{{cite web|title=Brooklyn Museum|url=http://www.brooklynmuseum.org/opencollection/objects/84178/Barred_Owl|work=Collections: American Art: Barred Owl}}</ref>
== References ==
{{Reflist|30em}}

== External links ==
{{Commons category|Strix varia|Barred owl}}
{{Wikispecies|Strix varia}}
* [https://web.archive.org/web/20170107042157/https://www.mbr-pwrc.usgs.gov/id/framlst/i3680id.html Barred Owl – ''Strix varia'']. USGS Patuxent Bird Identification InfoCenter
* [https://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Barred_Owl.html Barred Owl Species Account]. Cornell Lab of Ornithology
* {{InternetBirdCollection|barred-owl-strix-varia|Barred Owl}}
* {{VIREO|Barred+Owl|Barred Owl}}

{{Taxonbar|from=Q630457}}

{{DEFAULTSORT:owl, barred}}
[[Category:Birds described in 1799|barred owl]]
[[Category:Owls of North America|barred owl]]
[[Category:Strix (genus)|barred owl]]
[[Category:Taxa named by Benjamin Smith Barton|barred owl]]