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{{Short description|Genus, ''Sitta'', of small passerine birds from the Northern Hemisphere }}
{{pp-move|small=yes}}
{{Redirect|Sitta|the ancient capital of Sittacene|Sittace}}
{{distinguish|text=[[Sittella]], a songbird of the family Neosittidae}}
{{Automatic taxobox
| name = Nuthatches
| image = Sitta europaea -Rouge Cloitre estate, Sonian Forest, near Brussels, Belgium-8.jpg
| image_caption = A [[Eurasian nuthatch]] at the Rouge Cloître estate in the [[Sonian Forest]], near [[Brussels, Belgium]]
| display_parents = 2
| parent_authority = [[René Primevère Lesson|Lesson]], 1828
| taxon = Sitta
| authority = [[Carl Linnaeus|Linnaeus]], 1758
| type_species = ''[[Sitta europaea]]''
| type_species_authority = Linnaeus, 1758
}}
The '''nuthatches''' ({{IPAc-en|'|n|ʌ|t|h|æ|tʃ|}}) constitute a [[genus]], '''''Sitta''''', of small [[passerine]] [[bird]]s belonging to the family '''Sittidae'''. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs. Most species exhibit grey or bluish upper parts and a black eye stripe.

Most nuthatches breed in the temperate or [[montane forest|montane woodlands]] of the [[Northern Hemisphere]], although two species have adapted to rocky habitats in the warmer and drier regions of [[Eurasia]]. However, the greatest diversity is in [[South Asia|Southern Asia]], and similarities between the species have made it difficult to identify distinct species. All members of this genus nest in holes or crevices. Most species are [[bird migration|non-migratory]] and live in their habitat year-round, although the [[North America]]n [[red-breasted nuthatch]] migrates to warmer regions during the winter. A few nuthatch species have restricted ranges and face threats from [[deforestation]].

Nuthatches are [[Omnivore|omnivorous]], eating mostly [[insect]]s, [[Nut (fruit)|nut]]s, and [[seed]]s. They forage for insects hidden in or under bark by climbing along tree trunks and branches, sometimes upside-down. They forage within their territories when breeding, but they may join [[mixed-species feeding flock|mixed feeding flocks]] at other times. 

Their habit of wedging a large food item in a crevice and then hacking at it with their strong bills gives this group its English name.

==Taxonomy==
{{Phylogeny/Certhioidea}}
The nuthatch family, Sittidae, was described by [[René-Primevère Lesson]] in 1828.<ref>{{ cite book | last=Lesson | first=René | author-link=René Lesson | year=1828 | title=Manuel d'ornithologie, ou description des genres et des principales espèces d'oiseaux | volume=1 | language=fr | place=Paris | publisher=Roret | page=360 | url=https://biodiversitylibrary.org/page/55490443 }} Lesson used the French ''Sittées'' rather than the Latin Sittidae.</ref><ref name = Cracraft/> 

Sometimes the [[wallcreeper]] (''Tichodroma muraria''), which is restricted to the mountains of southern Eurasia, was placed in the same family as the nuthatches, but in a separate subfamily "Tichodromadinae", in which case the nuthatches were classified in the subfamily "Sittinae". However, the wallcreeper is now placed in a separate family, the Tichodromadidae.<ref name=BWP>Snow & Perrins (1998) pp. 1408</ref> The wallcreeper is intermediate in its [[morphology (biology)|morphology]] between the nuthatches and the [[treecreeper]]s, but its appearance, the texture of its plumage, and the shape and pattern of its tail suggest that it is closer to the nuthatches.<ref name="Vaurie">{{cite journal| last= Vaurie | first= Charles |author2=Koelz, Walter  |date=November 1950 | title= Notes on some Asiatic nuthatches and creepers| journal= [[American Museum Novitates]] | issue=1472 | pages= 1–39 | url = http://digitallibrary.amnh.org/dspace/bitstream/2246/4241/1/N1472.pdf }}</ref>

The next closest relatives to nuthatches after the wallcreeper, are the [[treecreeper]]s (Certhiidae) and [[Salpornis|spotted creepers]] (Salpornithidae), with these families placed in a larger grouping with the [[wren]]s (Troglodytidae) and [[gnatcatcher]]s (Polioptilidae). This [[superfamily (taxonomy)|superfamily]], the [[Certhioidea]], is proposed on [[phylogenetics|phylogenetic]] studies using [[mitochondria]]l and [[cell nucleus|nuclear]] DNA, and was created to cover a clade of families removed from a larger grouping of passerine birds, the [[Old World warbler|Sylvioidea]].<ref name = Cracraft>Cracraft, J.; Barker, F. Keith; Braun, M. J.; Harshman, J.; Dyke, G.; Feinstein, J.; Stanley, S.; Cibois, A.; Schikler, P.; Beresford, P.; García-Moreno, J.; Sorenson, M. D.; Yuri, T.; Mindell. D. P. (2004) "Phylogenetic relationships among modern birds (Neornithes): Toward an avian tree of life." pp. 468–489 in ''Assembling the tree of life'' (J. Cracraft and M. J. Donoghue, eds.). Oxford University Press, New York. {{ISBN|0-19-517234-5}}</ref><ref>{{cite journal|title=Monophyly and relationships of wrens (Aves: Troglodytidae):a congruence analysis of heterogeneous mitochondrial and nuclear DNA sequence data|author=Barker, F. Keith|year=2004|url=http://www.tc.umn.edu/~barke042/pdfs/Barker04.pdf|pmid=15062790|journal=Molecular Phylogenetics and Evolution|volume=31|issue=2|pages=486–504|doi=10.1016/j.ympev.2003.08.005|bibcode=2004MolPE..31..486B |archive-url=https://web.archive.org/web/20160412015810/http://www.tc.umn.edu/~barke042/pdfs/Barker04.pdf|archive-date=2016-04-12}}</ref>

The [[nuthatch vanga]] of [[Madagascar]] (formerly known as the coral-billed nuthatch) and the [[sittella]]s from [[Australia]] and [[New Guinea]] were once placed in the nuthatch family because of similarities in appearance and lifestyle, but they are not closely related. The resemblances arose via [[convergent evolution]] to fill an [[ecological niche]].<ref name="HQfamily">Harrap & Quinn (1996) pp. 16–17 "Family Introduction"</ref>
{{Cladogram
|caption=Phylogeny based on a molecular genetic study by Martin Päckert and colleagues published in 2020. The [[yellow-billed nuthatch]] (''Sitta solangiae'') was not sampled.<ref>{{ cite journal | last1=Päckert | first1=M. | last2=Bader-Blukott | first2=M.  | last3=Künzelmann | first3=B. | last4=Sun | first4=Y.-H. | last5=Hsu | first5=Y.-C. | last6=Kehlmaier | first6=C. | last7=Albrecht | first7=F. | last8=Illera | first8=J.C. | last9=Martens | first9=J. |  date=2020 | title=A revised phylogeny of nuthatches (Aves, Passeriformes, ''Sitta'') reveals insight in intra- and interspecific diversification patterns in the Palearctic | journal=Vertebrate Zoology | volume=70 | issue=2 | pages=241–262 | doi=10.26049/VZ70-2-2020-10 | doi-access=free }}</ref>
|align=right
|cladogram={{Clade| style=font-size:80%;line-height:75%;width:350px;
|label1=''Sitta''
|1={{clade
      |1={{clade
         |1=[[White-cheeked nuthatch]] (''Sitta leucopsis'')
         |2=[[Przevalski's nuthatch]] (''Sitta przewalskii'') 
         }}
      |2={{clade
         |1={{clade
            |1=[[White-breasted nuthatch]] (''Sitta carolinensis'')
            |2=[[Giant nuthatch]] (''Sitta magna'')
            }}
         |2={{clade
            |1={{clade
               |1=[[Beautiful nuthatch]] (''Sitta formosa'')
               |2={{clade
                  |1={{clade
                     |1=[[Blue nuthatch]] (''Sitta azurea'')
                     |2={{clade
                        |1=[[Velvet-fronted nuthatch]] (''Sitta frontalis'')
                        |2=[[Sulphur-billed nuthatch]] (''Sitta oenochlamys'')
                        }}
                     }}
                 |2={{clade
                    |1={{clade
                       |1=[[Pygmy nuthatch]] (''Sitta pygmaea'')
                       |2={{clade
                          |1=[[Bahama nuthatch]] (''Sitta insularis'')
                          |2=[[Brown-headed nuthatch]] (''Sitta pusilla'')
                          }}
                       }}
                    |2={{clade
                       |1={{clade
                          |1=[[Red-breasted nuthatch]] (''Sitta canadensis'')
                          |2={{clade
                             |1=[[Chinese nuthatch]] (''Sitta villosa'')
                             |2=[[Corsican nuthatch]] (''Sitta whiteheadi'')
                             }}
                          }}
                       |2={{clade
                          |1=[[Yunnan nuthatch]] (''Sitta yunnanensis'')
                          |2={{clade
                             |1=[[Krüper's nuthatch]] (''Sitta krueperi'')
                             |2=[[Algerian nuthatch]] (''Sitta ledanti'')
                             }}
                          }}  
                       }}
                    }}
                 }}
               }}
            |2={{clade
               |1={{clade
                  |1={{clade
                     |1=[[Western rock nuthatch]] (''Sitta neumayer'')
                     |2=[[Eastern rock nuthatch]] (''Sitta tephronota'')
                     }}
                  |2={{clade
                     |1=[[Siberian nuthatch]] (''Sitta arctica'')
                     |2={{clade
                        |1={{clade
                           |1=[[White-tailed nuthatch]] (''Sitta himalayensis'')
                           |2=[[White-browed nuthatch]] (''Sitta victoriae'')
                           }}
                        |2={{clade
                           |1=[[Eurasian nuthatch]] (''Sitta europaea'')
                           |2={{clade
                              |1=[[Chestnut-vented nuthatch]] (''Sitta nagaensis'')
                              |2={{clade
                                 |1=[[Kashmir nuthatch]] (''Sitta cashmirensis'')
                                 |2={{clade
                                    |1=[[Indian nuthatch]] (''Sitta castanea'')
                                    |2={{clade
                                       |1=[[Chestnut-bellied nuthatch]] (''Sitta cinnamoventris'')
                                       |2=[[Burmese nuthatch]] (''Sitta neglecta'')
                                       }}
                                    }}
                                 }}
                              }}
                           }}
                        }}
                     }}
                  }}
               }}
            }}
         }}
      }}
}}
}}

===Genus name===
The nuthatches are all in the genus ''Sitta'' [[Carl Linnaeus|Linnaeus]], 1758,<ref>{{cite book | last=Linnaeus | first=C. | author-link=Carl Linnaeus | title=Systema naturae per regna tria naturae |volume=I |edition=[[10th edition of Systema Naturae|10th]] | location=Stockholm |publisher=Laurentius Salvius |year=1758| quote =''Rostrum'' subcultrato-conicum, rectum, porrectum: integerrimum, mandíbula superiore obtusiuscula. ''Lingua'' lacero-emarginata |page= 115 | url=https://www.biodiversitylibrary.org/page/727020 }}</ref> a name derived from {{linktext|σίττη}} : {{Transliteration|grc|síttē}}, [[Ancient Greek]] for this bird.<ref name="Chambers">{{cite book | last = Brookes| first = Ian | title = The Chambers Dictionary | edition = ninth | year =2006 | publisher = Chambers | location = Edinburgh | isbn = 978-0-550-10185-3 |page = 1417 }}</ref> 

The English term ''nuthatch'' refers to the propensity of some species to wedge [[nut (fruit)|nuts]] or other large seeds in a crack and hack at it with their strong bills.<ref name="dict">{{cite web| title= Nuthatch | work= Merriam-Webster Online Dictionary |url= http://www.merriam-webster.com/dictionary/nuthatch | publisher= Merriam-Webster Online | access-date=2008-06-24}}</ref>

===Species boundaries===
In the 20th century and earlier, species boundaries in the nuthatches were sometimes difficult to define. The [[red-breasted nuthatch]], [[Corsican nuthatch]] and [[Chinese nuthatch]] have breeding ranges separated by thousands of kilometres, but are similar in habitat preference, appearance and song. They were formerly considered to be one species, but are now split into three<ref name="HQlimits">Harrap & Quinn (1996) pp. 12–13 "Species limits"</ref> and comprise a [[superspecies]] along with [[Kruper's nuthatch|Krüper's]] and [[Algerian nuthatch]]es. Unusually for nuthatches, all five species excavate their own nests.<ref name="Pasquet">{{cite journal| last=Pasquet | first= Eric |date=January 1998 | title= Phylogeny of the nuthatches of the ''Sitta canadensis'' group and its evolutionary and biogeographic implications | journal= Ibis | volume= 140 | issue= 1 | pages= 150–156 | doi =10.1111/j.1474-919X.1998.tb04553.x }}</ref>

The [[Eurasian nuthatch|Eurasian]], [[chestnut-vented nuthatch|chestnut-vented]], [[Kashmir nuthatch|Kashmir]] and [[chestnut-bellied nuthatch]]es form another superspecies and replace each other geographically across Asia. They are currently considered to be four separate species, but the south Asian forms were once believed to be a subspecies of the Eurasian nuthatch.<ref name="HQeurasian">Harrap & Quinn (1996) pp. 109–114 "Eurasian Nuthatch"</ref> A recent change in this taxonomy is a split of the chestnut-bellied nuthatch into three species, namely the Indian nuthatch, ''Sitta castanea'', found south of the [[Ganges]], the Burmese nuthatch, ''Sitta neglecta'', found in southeast Asia, and the chestnut-bellied nuthatch ''sensu stricto'', ''S.&nbsp;cinnamoventris'', which occurs in the [[Himalayas]].<ref name="Rasmussen">{{cite book| author = Rasmussen, Pamela C.|author2=Anderton, John C. |author-link2=John C. Anderton  | title = Birds of South Asia: The Ripley Guide | year = 2005 | publisher = Lynx Edicions, Barcelona. | isbn =978-84-87334-67-2 |page = 536 | author-link = Pamela C. Rasmussen|title-link=Birds of South Asia: The Ripley Guide }}</ref> Mitochondrial DNA studies have demonstrated that the white-breasted northern subspecies of Eurasian nuthatch, ''S.&nbsp;(europea) arctica'', is distinctive,<ref name="Zink">{{cite journal| last= Zink |first= Robert M. |author2= Drovetski, Sergei V.|author3=Rohwer, Sievert |date=September 2006 | title= Selective neutrality of mitochondrial ND2 sequences, phylogeography and species limits in ''Sitta europaea'' | journal=Molecular Phylogenetics and Evolution | volume=40| pmid= 16716603 | issue=3| pages= 679–686 | url =http://www.cbs.umn.edu/eeb/faculty/ZinkRobert/Selective%20neutrality.pdf | archive-url =https://web.archive.org/web/20090304212408/http://www.cbs.umn.edu/eeb/faculty/ZinkRobert/Selective%20neutrality.pdf | archive-date =2009-03-04 | doi = 10.1016/j.ympev.2005.11.002 |bibcode= 2006MolPE..40..679Z }}</ref> and also a possible candidate for full species status.<ref name="Dickinson"/> This split has been accepted by the [[British Ornithologists' Union]].<ref name= sangster2012>{{cite journal| last= Sangster | first= George |author2=Collinson, Martin |author3=Crochet, J. Pierre-André |author4=Knox, Alan G. |author5=Parkin, David T. |author6= Votier, Stephen C.  | year=2012 | title = Taxonomic recommendations for British birds: eighth report | journal= Ibis | volume=  154| issue = 4 | pages= 874–883| doi = 10.1111/j.1474-919X.2012.01273.x | doi-access= free }}</ref>

A 2006 review of Asian nuthatches suggested that there are still unresolved problems in nuthatch taxonomy and proposed splitting the genus ''Sitta''. This suggestion would move the red- and yellow-billed south Asian species ([[velvet-fronted nuthatch|velvet-fronted]], [[yellow-billed nuthatch|yellow-billed]] and [[sulphur-billed nuthatch]]es) to a new genus, create a third genus for the [[blue nuthatch]], and possibly a fourth for the [[beautiful nuthatch]].<ref name="Dickinson">{{cite journal |last=Dickinson |first=Edward C.|author-link=Edward C. Dickinson|year=2006 |title=Systematic notes on Asian birds. 62. A preliminary review of the Sittidae |journal=[[Zoologische Verhandelingen, Leiden]] |volume=80 |pages= 225–240 |format = PDF| url = http://www.repository.naturalis.nl/document/41857}}</ref>

The fossil record for this group appears to be restricted to a foot bone of an early [[Miocene]] bird from [[Bavaria]] which has been identified as an extinct representative of the climbing Certhioidea, a [[clade]] comprising the treecreepers, wallcreeper and nuthatches. It has been described as ''Certhiops rummeli''.<ref name="Manegold">{{cite journal | last= Manegold | first= Albrecht |date=April 2008 | title= Earliest fossil record of the Certhioidea (treecreepers and allies) from the early Miocene of Germany | journal= Journal of Ornithology | volume=149 | issue= 2 | pages= 223–228 | doi = 10.1007/s10336-007-0263-9| bibcode= 2008JOrni.149..223M | s2cid= 11900733 }}</ref> Two fossil species have been described in the genus ''Sitta'': ''S.&nbsp;cuvieri'' Gervais, 1852 and ''S.&nbsp;senogalliensis'' Portis, 1888, but they probably do not belong to nuthatches.<ref>
Jiří Mlíkovský, [http://www.nm.cz/download/JML-18-2002-CBE.pdf Cenozoic Birds of the World. Part 1:Europe] {{Webarchive|url=https://web.archive.org/web/20110520101755/http://www.nm.cz/download/JML-18-2002-CBE.pdf |date=2011-05-20 }} , Prague, Ninox Press, 2002, 407 p., p. 252, 273
</ref>

==Description==
[[File:Red-breasted-Nuthatch-3c.jpg|left|thumb|The red-breasted nuthatch is said to have a {{audio-nohelp|Sitta-canadensis-002.ogg|call}} like a tin trumpet.]]
Nuthatches are compact birds with short legs, compressed wings, and square 12-feathered tails. They have long, sturdy, pointed bills and strong toes with long claws. Nuthatches have blue-grey backs (violet-blue in some Asian species, which also have red or yellow bills) and white underparts, which are variably tinted with buff, orange, rufous or lilac. Although head markings vary between species, a long black eye stripe, with contrasting white [[supercilium]], dark forehead and blackish cap is common. The sexes look similar, but may differ in underpart colouration, especially on the rear flanks and under the tail. Juveniles and first-year birds can be almost indistinguishable from adults.<ref name="HQfamily"/>

The sizes of nuthatches vary,<ref name="HQfamily"/> from the large [[giant nuthatch]], at {{convert|195|mm|in|abbr=on}} and {{convert|36|–|47|g|oz|abbr=on}},<ref name="HQgiant">Harrap & Quinn (1996) pp. 169–172 "Giant Nuthatch"</ref> to the small [[brown-headed nuthatch]] and the [[pygmy nuthatch]], both around {{convert|100|mm|in|abbr=on}} in length and about {{convert|10|g|oz|abbr=on}}.<ref name="HQbhn">Harrap & Quinn (1996) pp. 130–133 "Brown-headed Nuthatch"</ref>

Nuthatches are very vocal, using an assortment of whistles, trills and calls. Their [[bird vocalization|breeding songs]] tend to be simple and often identical to their contact calls but longer in duration.<ref name="HQfamily"/> The red-breasted nuthatch, which coexists with the [[black-capped chickadee]] throughout much of its range, is able to understand the latter species' calls. The chickadee has subtle call variations that communicate information about the size and risk of potential predators. Many birds recognise the simple alarm calls produced by other species, but the red-breasted nuthatch is able to interpret the chickadees' detailed variations and to respond appropriately.<ref name="Templeton">{{cite journal| last= Templeton | first= Christopher N. |author2=Greene, Erick  |date=March 2007 | title= Nuthatches eavesdrop on variations in heterospecific chickadee mobbing alarm calls | journal= Proceedings of the National Academy of Sciences | volume= 104 | issue= 13 | pages= 5479–5482 | doi =10.1073/pnas.0605183104 | pmid= 17372225| pmc= 1838489| bibcode= 2007PNAS..104.5479T | doi-access= free }}</ref>

==Species==
The species diversity for Sittidae is greatest in southern Asia (possibly the original home of this family), where about 15 species occur, but it has representatives across much of the Northern Hemisphere.<ref name="HQfamily"/> The currently recognised nuthatch species are tabulated below.<ref name=ioc2>{{cite web| editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen | year=2020 | title=Nuthatches, Wallcreeper, treecreepers, mockingbirds, starlings, oxpeckers | work=IOC World Bird List Version 10.1 | url=https://www.worldbirdnames.org/bow/nuthatch/ | publisher=International Ornithologists' Union | access-date=15 June 2020 }}</ref>
<onlyinclude>
{| style="width:98%;" class="wikitable"
!  style="text-align:center; background:#d3d3a4;" colspan="4"|'''Species in [[taxonomic sequence]]'''
|-
!  style="width:23%; text-align:center;"|Common and<br/>binomial names
! Image
!  style="width:30%; text-align:center;"|Description
! style="text-align:center;"|Range <br/>(population if known)
|-
|[[White-cheeked nuthatch]]<br />(''Sitta leucopsis'')
|[[File:White-cheeked Nuthatch (Sitta leucopsis) (39661424053) (cropped).jpg|100px]]
|{{convert|13|cm|in|abbr=on}} long, white cheeks, chin, throat, and underparts, upper parts mostly dark grey.
|western Himalayas<ref name="HQwcn">Harrap & Quinn (1996) pp. 148–150 "White-cheeked Nuthatch"</ref>
|-
|[[Przevalski's nuthatch]]<br />(''Sitta przewalskii'')
|[[File:Przevalski's nuthatch - Chengdong Wang (cropped).jpg|100px]]
|{{convert|13|cm|in|abbr=on}} long, white cheeks, chin, throat, and underparts, upper parts mostly dark grey.
|southeastern Tibet to western China<ref>Rasmussen, P.C., and J.C. Anderton. 2005. Birds of South Asia. The Ripley guide. Volume 2: attributes and status. Smithsonian Institution and Lynx Edicions, Washington D.C. and Barcelona</ref>
|-
|[[Giant nuthatch]]<br />(''Sitta magna'')
|[[File:Giant nuthatch (Sitta magna).jpg|100px]]
|{{convert|19.5|cm|in|abbr=on}} long, greyish upper parts and whitish underparts.
|China, [[Burma]], and Thailand.<ref name="HQgiant" />
|-
|[[White-breasted nuthatch]]<br />(''Sitta carolinensis'')
|[[File:Sitta-carolinensis-001.jpg|100px]]
|{{convert|13|–|14|cm|in|abbr=on}} long, the white of the face completely surrounds the eye, face and the underparts are white, upper parts are mostly pale blue-grey.
|North America from southern Canada to Mexico<ref name="HQwbn">Harrap & Quinn (1996) pp. 150–155 "White-breasted Nuthatch"</ref><ref>Bull, John and Farrand, John Jr. ''The Audubon Society Field Guide to North American Birds, Eastern Region.'' Alfred A. Knopf, Inc. (1977) pp. 646–647 "White-breasted Nuthatch"</ref>
|-
|[[Beautiful nuthatch]]<br />(''Sitta formosa'')
|[[File:Beautiful Nuthatch - Eaglenest - India (cropped).jpg|100px]]
|{{convert|16.5|cm|in|abbr=on}} long, black-backed with white streaking, bright blue upper back, rump and shoulders, dull orange underparts and paler face.
|Northeast India and Burma and locally in southern China and northern Southeast Asia<ref name="HQbeauty">Harrap & Quinn (1996) pp. 172–173 "Beautiful Nuthatch"</ref>
|-
|[[Blue nuthatch]]<br />(''Sitta azurea'')
|[[File:Blue Nuthatch - Cibodas Botanical Garden, Java, Indonesia (cropped).jpg|100px]]
|{{convert|13.5|cm|in|abbr=on}} long, greyish upper parts and whitish underparts.
|[[Malaysia]], [[Sumatra]] and [[Java]]<ref name="HQbluen">Harrap & Quinn (1996) pp. 168–169 "Blue Nuthatch"</ref>
|-
|[[Velvet-fronted nuthatch]]<br />(''Sitta frontalis'')
|[[File:Velvet-fronted Nuthatch, Ganeshgudi, 26 FEB 2016, Vimal Rajyaguru,1 (cropped 2).jpg|100px]]
|{{convert|12.5|cm|in|abbr=on}} long, violet-blue above, with lavender cheeks, beige underparts and a whitish throat, bill is red, black patch on forehead.
|India and [[Sri Lanka]] through [[Southeast Asia]] to [[Indonesia]]<ref name="HQvfn">Harrap & Quinn (1996) pp. 161–164 "Velvet-fronted Nuthatch"</ref>
|-
|[[Yellow-billed nuthatch]]<br />(''Sitta solangiae'')
|[[File:Sitta solangiae 5354.jpg|100px]]
|{{convert|12.5|–|13.5|cm|in|abbr=on}} long, white underparts, bluish upper parts, yellow beak.
|Vietnam and [[Hainan Island]], China<ref name="HQybn">Harrap & Quinn (1996) pp. 164–165 "Yellow-billed Nuthatch"</ref>
|-
|[[Sulphur-billed nuthatch]]<br />(''Sitta oenochlamys'')
|[[File:Sulfur-billed Nuthatch crop (cropped).jpg|100px]]
|{{convert|12.5|cm|in|abbr=on}} long, pinkish underparts, yellow beak, bluish upper parts.
|Endemic to the [[Philippines]]<ref name="HQsbn">Harrap & Quinn (1996) pp. 165–168 "Sulphur-billed Nuthatch"</ref>
|-
|[[Pygmy nuthatch]]<br />(''Sitta pygmaea'')
|[[File:Pygmy Nuthatch (Sitta pygmaea) at a feeder.jpg|100px]]
|{{convert|10|cm|in|abbr=on}} long, grey cap, blue-grey upper parts, whitish underparts, whitish spot on the nape.
|Western North America from [[British Columbia]] to southwest [[Mexico]]<br />(2.3&nbsp;million)<ref name="HQpigmy">Harrap & Quinn (1996) pp. 127–130 "Pygmy Nuthatch"</ref>
|-
|[[Brown-headed nuthatch]]<br />(''Sitta pusilla'')
|[[File:Brown-headed Nuthatch-27527-4c.jpg|100px]]
|{{convert|10.5|cm|in|abbr=on}} long, brown cap with narrow black eye stripe and buff white cheeks, chin, and belly, wings are bluish-grey, small white spot at the nape of the neck.
|Endemic to the Southeastern [[United States]]<br />(1.5&nbsp;million)<ref name="HQbhn" />
|-
|[[Bahama nuthatch]] 
(''Sitta insularis'')
|
|Very similar to brown-headed nuthatch, but has a darker eye stripe, much longer beak, shorter wings, and a different call than it.
|Endemic to [[Grand Bahama]]
(1–49 individuals, potentially extinct)<ref>{{Cite web|last=International)|first=BirdLife International (BirdLife|date=2020-08-27|title=IUCN Red List of Threatened Species: Sitta insularis|url=https://www.iucnredlist.org/en|access-date=2021-07-14|website=IUCN Red List of Threatened Species}}</ref>
|-
|[[Yunnan nuthatch]]<br />(''Sitta yunnanensis'')
|[[File:Yunnan nuthatch.jpg|100px]]
|{{convert|12|cm|in|abbr=on}} long, greyish upper parts and whitish underparts.
|Endemic to southwest China<ref name="HQyunnan">Harrap & Quinn (1996) pp. 143–144 "Yunnan Nuthatch"</ref>
|-
|[[Algerian nuthatch]]<br />(''Sitta ledanti'')
|[[File:Sitta ledanti - Karim Haddad (cropped).jpeg|100px]]
|{{convert|13.5|cm|in|abbr=on}} long, blue-grey above, and buff below. Male has a black crown and eye stripe separated by a white supercilium; female has a grey crown and eye stripe.
|Endemic to northeast [[Algeria]]<br />(Fewer than 1,000 pairs)<ref name="HQalgerian">Harrap & Quinn (1996) pp. 135–138 "Algerian Nuthatch"</ref>
|-
|[[Krüper's nuthatch]]<br />(''Sitta krueperi'')
|[[File:090503 Krupers nuthatch east of Gulf of Kalloni.jpg|100px]]
|{{convert|11.5|–|12.5|cm|in|abbr=on}} long, whitish underparts with a reddish throat, mostly grey upper parts.
|[[Turkey]], [[Georgia (country)|Georgia]], [[Russia]] and on the [[Greece|Greek]] island of [[Lesbos Island|Lesvos]].<br />(80,000–170,000 pairs)<ref name="HQkruper">Harrap & Quinn (1996) pp. 138–140 "Krüper's Nuthatch"</ref>
|-
|[[Red-breasted nuthatch]]<br />(''Sitta canadensis'')
|[[File:Red-breasted Nuthatch (Sitta canadensis)10-4c.jpg|100px]]
|{{convert|11|cm|in|abbr=on}} long, blue-grey upper parts, with reddish underparts, white face with a black eye stripe, white throat, a straight grey bill and a black crown.
|Western and northern temperate North America, winters across much of the US and southern [[Canada]]<br />(18&nbsp;million)<ref name="HQrbn">Harrap & Quinn (1996) pp. 144–148 "Red-breasted Nuthatch"</ref>
|-
|[[Corsican nuthatch]]<br />(''Sitta whiteheadi'')
|[[File:Sitta whiteheadi - Christoph Moning - 4 (cropped).jpeg|100px]]
|{{convert|12|cm|in|abbr=on}} long, blue-grey above, and buff below. Male has a black crown and eye stripe separated by a white [[supercilium]]; the female has a grey crown and eye stripe.
|Endemic to [[Corsica]]<br />(c. 2,000 pairs)<ref name="HQcorsican">Harrap & Quinn (1996) pp. 133–135 "Corsican Nuthatch"</ref><ref>{{cite journal|last1=Thibault|first1=Jean-Claude|last2=Hacquemand|first2=Didier|last3=Moneglia|first3=Pasquale|last4=Pellegrini|first4=Hervé|last5=Prodon|first5=Roger|last6=Recorbet|first6=Bernard|last7=Seguin|first7=Jean-François|last8=Villard|first8=Pascal|year=2011|title=Distribution and population size of the Corsican Nuthatch ''Sitta whiteheadi''|journal=Bird Conservation International|volume=21|issue=2|pages=199–206|doi=10.1017/S0959270910000468|doi-access=free}}</ref>
|-
|[[Chinese nuthatch]]<br />(''Sitta villosa'')
|[[File:Sitta villosa - Kim, Hyun-tae (4) (cropped).jpg|100px]]
|{{convert|11.5|cm|in|abbr=on}} long, greyish upper parts and pinkish underparts.
|China, North Korea, and South Korea<ref name="HQchinese">Harrap & Quinn (1996) pp. 140–142 "Chinese Nuthatch"</ref>
|-
|[[Western rock nuthatch]]<br />(''Sitta neumayer'')
|[[File:Sitta neumayer - Western Rock Nuthatch, Mersin 2016-11-20 06-1.jpg|100px]]
|{{convert|13.5|cm|in|abbr=on}} long. white throat and underparts shading to buff on the belly. The shade of grey upper parts and the darkness of the eye stripe vary between the three subspecies.
|The [[Balkans]] east through [[Greece]] and [[Turkey]] to [[Iran]]<br />(130,000)<ref name="HQwrock">Harrap & Quinn (1996) pp. 155–158 "Western Rock Nuthatch"</ref>
|-
|[[Eastern rock nuthatch]]<br />(''Sitta tephronota'')
|[[File:Tahtseyok.jpg|100px]]
|{{convert|16|–|18|cm|in|abbr=on}} long, greyish upper parts and whitish underparts, pinkish rump.
|Northern [[Iraq]] Kurdistan and western Iran east through [[Central Asia]]<br />(43,000–100,000 in Europe)<ref name="HQerock">Harrap & Quinn (1996) pp. 158–161 "Eastern Rock Nuthatch"</ref>
|-
|[[Siberian nuthatch]]<br />(''Sitta arctica'')
|[[File:Sitta arctica png.png|100px]]
|{{convert|15|cm|in|abbr=on}} long, long and thin bill, black eye stripe, blue-grey upper parts, pure white underparts, long claw.
|Eastern [[Siberia]]
|-
|[[White-browed nuthatch]]<br />(''Sitta victoriae'')
|[[File:2M3A6919 - White-browed Nuthatch - Sitta victoriae (cropped).jpg|100px]]
|{{convert|11.5|cm|in|abbr=on}} long, greyish upper parts and mostly whitish underparts.
|[[Endemism|Endemic]] to [[Myanmar]]<ref name="HQwbn1">Harrap & Quinn (1996) pp. 125–126 "White-browed Nuthatch"</ref>
|-
|[[White-tailed nuthatch]]<br />(''Sitta himalayensis'')
|[[File:White-tailed Nuthatch Sitta himalayensis perches on a branch, India 2016.jpg|100px]]
|{{convert|12|cm|in|abbr=on}} long, smaller bill than ''S.&nbsp; cashmirensis'', rufous-orange underparts with unmarked bright rufous undertail-coverts, white on the upper tail coverts is difficult to see in the field.
|[[Himalayas]] from northeast India to southwest [[China]], locally east to [[Vietnam]]<ref name="HQwtn">Harrap & Quinn (1996) pp. 123–125 "White-tailed Nuthatch"</ref>
|-
|[[Eurasian nuthatch]]<br/>(''Sitta europaea'')
|[[File:Eurasian Nuthatch (Sitta europaea) -modified.jpg|100px]]
|{{convert|14|cm|in|abbr=on}} long, black eye stripe, blue-grey upper parts, reddish and/or white underparts depending on subspecies.
|Temperate [[Eurasia]]<br/>(10&nbsp;million)<ref name="HQeurasian"/>
|-
|[[Chestnut-vented nuthatch]]<br />(''Sitta nagaensis'')
|[[File:Chestnut-vented nuthatch (cropped).jpg|100px]]
|{{convert|12.5|–|14|cm|in|abbr=on}} long, mostly pale grey upper parts and mostly whitish underparts, dark eye stripe.
|Northeast [[India]] east to northwest [[Thailand]]<ref name="HQcvn">Harrap & Quinn (1996) pp. 114–117 "Chestnut-vented Nuthatch"</ref>
|-
|[[Kashmir nuthatch]]<br/>(''Sitta cashmirensis'')
|[[File:Kashmir Nuthatch (Sitta cashmirensis) (48553160711) (cropped).jpg|100px]]
|{{convert|14|cm|in|abbr=on}} long, mostly greyish upper parts, reddish underparts with a paler throat and chin.
|Eastern [[Afghanistan]] to western [[Nepal]]<ref name="HQkashmir">Harrap & Quinn (1996) pp. 117–119 "Kashmir Nuthatch"</ref>
|-
|[[Indian nuthatch]]<br />(''Sitta castanea'')
|[[File:Chestnut-bellied Nuthatch.jpg|100px]]
|{{convert|13|cm|in|abbr=on}} long.
|Northern and central India<ref name="Rasmussen" /><ref name="HQcbn" />
|-
|[[Chestnut-bellied nuthatch]]<br/>(''Sitta cinnamoventris'')
|[[File:Chestnut-bellied Nuthatch Ghatgarh Uttarakhand India 03.12.2014.jpg|100px]]
|{{convert|13|cm|in|abbr=on}} long, colours vary between the subspecies.
| Foothills of the Himalayas from northeast India to western [[Yunnan]] and Thailand<ref name="Rasmussen"/><ref name="HQcbn">Harrap & Quinn (1996) pp. 119–123 "Chestnut-bellied Nuthatch"</ref>
|-
|[[Burmese nuthatch]]<br/>(''Sitta neglecta'')
|[[File:Sitta neglecta.svg|100px]]
|{{convert|13|cm|in|abbr=on}} long.
| Myanmar to Laos, Cambodia and southern Vietnam<ref name="Rasmussen"/><ref name="HQcbn"/>
|}
</onlyinclude>

==Distribution and habitat==
[[File:Pinus ponderosa 8144t.jpg|upright|thumb|Open [[ponderosa pine]] woodlands are a habitat for [[pygmy nuthatch]].]]
Members of the nuthatch family live in most of North America and Europe and throughout Asia down to the [[Wallace Line]]. Nuthatches are sparsely represented in Africa; one species lives in a small area of northeastern Algeria<ref name="BWP1400">Snow & Perrins (1998) pp. 1400–1401 "Algerian Nuthatch"</ref> and a population of the Eurasian nuthatch subspecies, ''S.&nbsp;e.&nbsp;hispaniensis'', lives in the mountains of [[Morocco]].<ref name="BWP1402">Snow & Perrins (1998) pp. 1402–1404 "Nuthatch"</ref> Most species are resident year-round. The only significant migrant is the red-breasted nuthatch, which winters widely across North America, deserting the northernmost parts of its breeding range in Canada; it has been recorded as a vagrant in [[Bermuda]], [[Iceland]] and England.<ref name="HQrbn"/>

Most nuthatches are woodland birds and the majority are found in [[conifer]]ous or other [[evergreen]] forests, although each species has a preference for a particular tree type. The strength of the association varies from the Corsican nuthatch, which is closely linked with [[European black pine|Corsican pine]], to the catholic habitat of the Eurasian nuthatch, which prefers [[deciduous]] or mixed woods but breeds in coniferous forests in the north of its extensive range.<ref name="BWP1402"/><ref name="BWP1399">Snow & Perrins (1998) pp. 1399–1400 "Corsican nuthatch"</ref> However, the two species of rock nuthatches are not strongly tied to woodlands: they breed on rocky slopes or cliffs, although both move into wooded areas when not breeding.<ref name="BWP1404">Snow & Perrins (1998) pp. 1404–1406 "Eastern Rock Nuthatch"</ref><ref name = "BWP1406"/> In parts of Asia where several species occur in the same geographic region, there is often an altitudinal separation in their preferred habitats.<ref>{{cite journal|last=Menon|first=Shaily|author2=Islam, Zafar-Ul |author3=Soberón, Jorge |author4=Peterson, A. Townsend |year=2008|title=Preliminary analysis of the ecology and geography of the Asian nuthatches (Aves: Sittidae)|journal=The Wilson Journal of Ornithology|volume=120|issue=4|pages=692–699|doi=10.1676/07-136.1|s2cid=11556921|url=https://scholarworks.gvsu.edu/cgi/viewcontent.cgi?article=1001&context=biopeerpubs|url-access=subscription}}</ref><ref>{{cite journal|last=Ripley|first=S. Dillon|year=1959|title=Character displacement in Indian nuthatches (Sitta)|journal=Postilla|volume=42|pages=1–11|url=https://archive.org/details/postilla150peab}}</ref>

Nuthatches prefer a fairly temperate climate; northern species live near sea level whereas those further south are found in cooler highland habitats. Eurasian and red-breasted nuthatches are lowland birds in the north of their extensive ranges, but breed in the mountains further south; for example, the Eurasian nuthatch, which breeds where the July temperature range is {{convert|16|-|27|C|F}}, is found near sea level in Northern Europe, but between {{convert|1,750|and|1,850|m|ft|abbr=on}} altitude in Morocco.<ref name="BWP1402"/> The velvet-fronted nuthatch is the sole member of the family which prefers tropical lowland forests.<ref name="HQvfn"/>

==Behaviour==

===Nesting, breeding and survival===
[[File:NuthatchNest.svg|thumb|right| Cross-section of a western rock nuthatch nest cavity with a mud wall and tunnel across its entrance]]
[[File:Pygmy nuthatch creating cavity.webm|thumb|thumbtime=105|A [[pygmy nuthatch]] creating a cavity through the fibrous tissue in the stub of a pruned dead [[Canary Island Date Palm]] frond.]]
All nuthatches nest in cavities; except for the two species of rock nuthatches, all use tree holes, making a simple cup lined with soft materials on which to rest eggs. In some species the lining consists of small woody objects such as bark flakes and seed husks, while in others it includes the moss, grass, hair and feathers typical of passerine birds.<ref name="HQeurasian"/><ref name="HQpigmy"/>

Members of the red-breasted nuthatch superspecies excavate their own tree holes, although most other nuthatches use natural holes or old [[woodpecker]] nests. Several species reduce the size of the entrance hole and seal up cracks with mud. The red-breasted nuthatch makes the nest secure by daubing sticky conifer [[resin]] globules around the entrance, the male applying the resin outside and the female inside. The resin may deter predators or competitors (the resident birds avoid the resin by diving straight through the entrance hole).<ref name="Cornellrbn">{{cite web| title= Red-breasted Nuthatch | work= Bird Guide | url= https://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Red-breasted_Nuthatch_dtl.html| publisher= Cornell Laboratory of Ornithology | access-date=2008-06-20}}</ref> The white-breasted nuthatch smears [[blister beetle]]s around the entrance to its nest, and it has been suggested that the unpleasant smell from the crushed insects deters [[squirrel]]s, its chief competitor for natural tree cavities.<ref name="Kilham">{{cite journal| last= Kilham | first= Lawrence |date=January 1971 | title= Use of in bill-sweeping by White-breasted Nuthatch | journal= The Auk | volume=88 | issue= 1 | pages= 175–176 | url =http://sora.unm.edu/sites/default/files/journals/auk/v088n01/p0175-p0176.pdf | doi= 10.2307/4083981| jstor= 4083981 }}</ref>

The western rock nuthatch builds an elaborate flask-shaped nest from mud, dung and hair or feathers, and decorates the nest's exterior and nearby crevices with feathers and insect wings. The nests are located in rock crevices, in caves, under cliff overhangs or on buildings.<ref name="HQwrock"/> The eastern rock nuthatch builds a similar but less complex structure across the entrance to a cavity. Its nest can be quite small but may weigh up to 32&nbsp;[[kilogram|kg]] (70&nbsp;[[pound (mass)|lb]]). This species will also nest in river banks or tree holes and will enlarge its nest hole if it the cavity is too small.<ref name="HQerock"/>

[[File:Dendrocopos major 4-3c.jpg|upright|thumb|left|The [[great spotted woodpecker]] is an important predator of Eurasian nuthatch nests.<ref name="Varo">{{cite journal| last=González-Varo | first= Juan P |author2=López-Bao, José V.|author3=Guitián, José | year=2008 | title= Presence and abundance of the Eurasian nuthatch ''Sitta europaea'' in relation to the size, isolation and the intensity of management of chestnut woodlands in the NW Iberian Peninsula | journal= Landscape Ecology | volume= 23| issue= 1 | pages=79–89 | doi =10.1007/s10980-007-9166-7| bibcode= 2008LaEco..23...79G | s2cid= 19446422 }}</ref>]]
Nuthatches are [[monogamy in animals|monogamous]]. The female produces eggs that are white with red or yellow markings; the clutch size varies, tending to be larger for northern species. The eggs are incubated for 12 to 18 days by the female alone, or by both parents, depending on the species. The [[altricial]] (naked and helpless) chicks take between 21 and 27 days to fledge.<ref name="HQerock"/><ref name="BWP1406">Snow & Perrins (1998) pp. 1406–1407 "Rock Nuthatch"</ref><ref name="BWPintro">Snow & Perrins (1998) p. 1398 "Nuthatch: Family Sittidae"</ref><ref name="Matthysen & Löhrl">{{cite book | last = Matthysen | first = Erik | author2 = Löhrl, Hans | chapter = Nuthatches | editor = Perrins, Christopher | editor-link = Christopher Perrins | title = Firefly Encyclopedia of Birds | publisher = Firefly Books | year = 2003 | pages = [https://archive.org/details/fireflyencyclope0000unse/page/536 536–537] | isbn = 978-1-55297-777-4 | chapter-url-access = registration | chapter-url = https://archive.org/details/fireflyencyclope0000unse | url = https://archive.org/details/fireflyencyclope0000unse/page/536 }}</ref> Both parents feed the young, and in the case of two American species, brown-headed and pygmy, [[helpers at the nest|helper]] males from the previous brood may assist the parents in feeding.<ref name="ADWpygmy"/><ref name="Cornellbhn">{{cite web| title= Brown-headed Nuthatch | work= Bird Guide | url= https://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Brown-headed_Nuthatch_dtl.html | publisher= Cornell Laboratory of Ornithology | access-date=2008-06-21}}</ref>

For the few species on which data are available, the average nuthatch lifespan in the wild is between 2 and 3.5&nbsp;years, although ages of up to 10 years have been recorded.<ref name="ADWpygmy">{{cite web| author = Kieliszewski, Jordan | title= ''Sitta pygmaea'' | work= Animal Diversity Web| url= http://animaldiversity.ummz.umich.edu/site/accounts/information/Sitta_pygmaea.html | publisher= University of Michigan Museum of Zoology | access-date=2008-06-21}}</ref><ref name="ADWwbn">{{cite web|author1=Roof, Jennifer |author2=Dewey, Tanya | title= ''Sitta carolinensis'' | work= Animal Diversity Web| url= http://animaldiversity.ummz.umich.edu/site/accounts/information/Sitta_carolinensis.html | publisher= University of Michigan Museum of Zoology | access-date=2008-06-21}}</ref> The Eurasian nuthatch has an adult annual [[survival rate]] of 53%<ref name="BTO">{{cite web| title= Nuthatch ''Sitta europaea'' [Linnaeus, 1758&#93; | work= BTO Birdfacts | url= http://blx1.bto.org/birdfacts/results/bob14790.htm | publisher= [[British Trust for Ornithology]]| access-date=2008-12-01}}</ref> and the male Corsican nuthatch 61.6%.<ref name="Thibault">{{cite journal| last= Thibault | first= Jean-Claude |author2=Jenouvrier, Stephanie  | year=2006 | title= Annual survival rates of adult male Corsican nuthatches ''Sitta whiteheadi'' | journal= [[Ringing & Migration]] | volume= 23 | pages= 85–88 | url = http://blx1.bto.org/pdf/ringmigration/23_2/thibault.pdf | doi= 10.1080/03078698.2006.9674349| issue= 2| s2cid= 85182636 | doi-access= free }}</ref> Nuthatches and other small woodland birds share the same predators: [[accipiter]]s, [[owl]]s, squirrels and woodpeckers. An American study showed that nuthatch responses to predators may be linked to reproductive strategies. It measured the willingness of males of two species to feed incubating females on the nest when presented with models of a [[sharp-shinned hawk]], which hunts adult nuthatches, or a [[Northern house wren|house wren]], which destroys eggs. The white-breasted nuthatch is shorter-lived than the red-breasted nuthatch, but has more young, and was found to respond more strongly to the egg predator, whereas the red-breasted showed greater concern with the hawk. This supports the theory that longer-lived species benefit from adult survival and future breeding opportunities while birds with shorter life spans place more value on the survival of their larger broods.<ref name="Ghalambor">{{cite journal| last= Ghalambor | first= Cameron K. |author2=Martin, Thomas E.  |date=August 2000 | title= Parental investment strategies in two species of nuthatch vary with stage-specific predation risk and reproductive effort | journal=Animal Behaviour | volume=60| pmid= 10973729 | issue=2 | pages=263–267 | url = http://www.umt.edu/mcwru/personnel/martin/PDF%20Martin/Reprint577.pdf | doi =10.1006/anbe.2000.1472| s2cid= 13165711 }}</ref>

Cold can be a problem for small birds that do not migrate. [[Communal roosting]] in tight huddles can help conserve heat and several nuthatch species employ it&mdash;up to 170 pygmy nuthatches have been seen in a single roost. The pygmy nuthatch is able to lower its body temperature when roosting, conserving energy through [[hypothermia]] and a lowered [[basal metabolic rate|metabolic rate]].<ref name="ADWpygmy"/>

===Feeding===
[[File:2017.07.05.-14-NaturCampingplatz am Springsee-Storkow (Mark)--Kleiber-Maennchen.jpg|thumb|upright|Eurasian nuthatch prying something out from under the bark of a tree]]
Nuthatches forage along tree trunks and branches and are members of the same [[Guild (ecology)|feeding guild]] as woodpeckers. Unlike woodpeckers and [[Certhia|treecreepers]], however, they do not use their tails for additional support, relying instead on their strong legs and feet to progress in jerky hops.<ref name="Matthysen & Löhrl"/><ref>{{cite journal|author1=Fujita, M. |author2= K. Kawakami |author3=S. Moriguchi |author4=H. Higuchi  |name-list-style=amp |title=Locomotion of the Eurasian nuthatch on vertical and horizontal substrates|journal=Journal of Zoology |volume=274 |issue=4 |pages=357–366 |year=2008 |doi= 10.1111/j.1469-7998.2007.00395.x}}</ref> They are able to descend head-first and hang upside-down beneath twigs and branches. Krüper's nuthatch can even stretch downward from an upside-down position to drink water from leaves without touching the ground.<ref name="Albayrak">{{cite journal | last= Albayrak | first= Tamer | author2= Erdoğan, Ali | year= 2005 | title= Observations on some behaviours of Krüper's Nuthatch (''Sitta krueperi''), a little-known West Palaearctic bird | journal= Turkish Journal of Zoology | volume= 29 | pages= 177–181 | url= http://journals.tubitak.gov.tr/zoology/issues/zoo-05-29-2/zoo-29-2-12-0203-8.pdf | access-date= 2008-06-27 | archive-url= https://web.archive.org/web/20090225143555/http://journals.tubitak.gov.tr/zoology/issues/zoo-05-29-2/zoo-29-2-12-0203-8.pdf | archive-date= 2009-02-25 }}</ref> Rock nuthatches forage with a similar technique to the woodland species, but seek food on rock faces and sometimes buildings. When breeding, a pair of nuthatches will only feed within their territory, but at other times will associate with passing [[tit (bird)|tits]] or join [[mixed-species feeding flock]]s.<ref name="HQfamily"/><ref name="BWPintro"/><ref name="Robson">{{cite book | last = Robson | first = Craig | title = A Field Guide to the Birds of Thailand | year = 2004 | publisher = New Holland Press |page = 204 | isbn = 978-1-84330-921-5}}</ref>

[[Insect]]s and other [[invertebrate]]s are a major portion of the nuthatch diet, especially during the breeding season, when they rely almost exclusively on live prey,<ref name="ADWwbn"/> but most species also eat seeds during the winter, when invertebrates are less readily available. Larger food items, such as big insects, [[snail]]s, [[acorn]]s or seeds may be wedged into cracks and pounded with the bird's strong bill.<ref name="HQfamily"/> Unusually for a bird, the brown-headed nuthatch uses a piece of tree bark as a lever to pry up other bark flakes to look for food; the bark tool may then be carried from tree to tree or used to cover a seed [[cache (biology)|cache]].<ref name="Cornellbhn"/>

All nuthatches appear to store food, especially seeds, in tree crevices, in the ground, under small stones, or behind bark flakes, and these caches are remembered for as long as 30 days.<ref name="HQeurasian"/><ref name="HQpigmy"/><ref>{{cite journal| last= Hardling | first= Roger |author2=Kallander, Hans|author3=Nilsson, Jan-Åke | year=1997 | title= Memory for hoarded food: an aviary study of the European Nuthatch | journal=[[The Condor (journal)|The Condor]] | volume=99 | issue= 2| pages= 526–529 | url = http://sora.unm.edu/sites/default/files/journals/condor/v099n02/p0526-p0529.pdf | doi= 10.2307/1369961| jstor= 1369961}}</ref> Similarly, the rock nuthatches wedge snails into suitable crevices for consumption in times of need.<ref name="HQwrock"/><ref name="HQerock"/> European nuthatches have been found to avoid using their caches during benign conditions in order to save them for harsher times.<ref>{{cite journal| last= Nilsson | first= Jan-Åke |author2=Persson, Hans Källander Owe | year=1993 | title= A prudent hoarder: effects of long-term hoarding in the European nuthatch, ''Sitta europaea'' | journal= Behavioral Ecology | volume=4 | issue= 4| pages= 369–373| doi= 10.1093/beheco/4.4.369}}</ref>

==Conservation status==
[[File:Kowalik5.jpg|thumb|left|[[White-breasted nuthatch]], common in much of North America]]
Some nuthatches, such as the Eurasian nuthatch and the North American species, have extensive ranges and large populations, and few conservation problems,<ref name="Birdlife">{{cite web| title= ''Sitta'' | work= Species Search Results | url= http://www.birdlife.org/datazone/species/index.html?action=SpcHTMFindResults.asp&hdnAction=SEARCH&hdnPageMode=0&cboFamily=-2&txtGenus=sitta&txtSpecies=&txtCommonName=&cboRegion=-2&cboCountry=-2| publisher= [[BirdLife International]] | access-date=2008-06-21}}</ref> although locally they may be affected by woodland fragmentation.<ref name="Varo"/><ref name="vanLangeveld">{{cite journal| last= van Langevelde | first= Frank | year=2000 | title= Scale of habitat connectivity and colonization in fragmented nuthatch populations | journal= Ecography | volume=23 | issue= 5 | pages= 614–622 | jstor = 3683295 | doi = 10.1111/j.1600-0587.2000.tb00180.x| doi-access= free | bibcode= 2000Ecogr..23..614V }}</ref> In contrast, some of the more restricted species face severe pressures.

The [[Endangered species|endangered]] white-browed nuthatch is found only in the [[Nat Ma Taung|Mount Victoria]] area of Burma, where forest up to {{convert|2,000|m|ft|abbr=on}} above sea level has been almost totally cleared and habitat between {{convert|2,000|–|2,500|m|ft|abbr=on}} is heavily degraded. Nearly 12,000 people live in the Natma Taung [[national park]] which includes Mount Victoria, and their fires and traps add to the pressure on the nuthatch. The population of the white-browed nuthatch, estimated at only a few thousand, is decreasing, and no conservation measures are in place.<ref>{{cite iucn |author=BirdLife International |date=2016 |title=''Sitta victoriae'' |volume=2016 |article-number=e.T22711167A94281752 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22711167A94281752.en |access-date=11 November 2021}}</ref><ref name="ThetZawNaing">{{cite journal| author = Thet Zaw Naing | year= 2003| title= Ecology of the White-browed Nuthatch ''Sitta victoriae'' in Natmataung National Park, Myanmar, with notes on other significant species | journal= Forktail | volume= 19 | pages= 57–62 | url =http://birdingasia.org/wp-content/uploads/2012/09/Naing-Nuhatch.pdf }}</ref> The Algerian nuthatch is found in only four areas of Algeria, and it is possible that the total population does not exceed 1,000 birds. Fire, erosion, and grazing and disturbance by livestock have reduced the quality of the habitat, despite its location in the Taza National Park.<ref name="Sittaledanti">{{cite iucn |author=BirdLife International |date=2017 |title=''Sitta ledanti'' |volume=2017 |article-number=e.T22711179A119435091 |doi=10.2305/IUCN.UK.2017-3.RLTS.T22711179A119435091.en |access-date=11 November 2021}}</ref>

Deforestation has also caused population declines for the [[Vulnerable species|vulnerable]] Yunnan and yellow-billed nuthatches. The Yunnan nuthatch can cope with some tree loss, since it prefers open pine woodland, but although still locally common, it has disappeared from several of the areas in which it was recorded in the early 20th century.<ref>{{cite iucn |author=BirdLife International |date=2017 |title=''Sitta yunnanensis'' |volume=2017 |article-number=e.T22711192A116898695 |doi=10.2305/IUCN.UK.2017-3.RLTS.T22711192A116898695.en |access-date=11 November 2021}}</ref> The threat to yellow-billed is particularly acute on Hainan, where more than 70% of the woodland has been lost in the past 50 years due to shifting cultivation and the use of wood for fuel during Chinese government re-settlement programmes.<ref>{{cite iucn |author=BirdLife International |date=2018 |title=''Sitta solangiae'' |volume=2018 |article-number=e.T22711219A132095305 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22711219A132095305.en |access-date=11 November 2021}}</ref>

Krüper's nuthatch is threatened by urbanisation and development in and around mature coniferous forests, particularly in the [[Mediterranean]] coastal areas where the species was once numerous. A law promoting tourism came into force in Turkey in 2003, further exacerbating the threats to their habitat. The law reduced bureaucracy and made it easier for developers to build tourism facilities and summer houses in the coastal zone where woodland loss is a growing problem for the nuthatch.<ref name="Sittakrueperi">{{cite iucn |author=BirdLife International |date=2016 |title=''Sitta krueperi'' |volume=2016 |article-number=e.T22711184A94282660 |doi=10.2305/IUCN.UK.2016-3.RLTS.T22711184A94282660.en |access-date=11 November 2021}}</ref><ref name=Turkey>{{cite web | title=Turkey: briefing notes on tourism policy and institutional framework | url=http://www.transanatolie.com/turkce/turkiye/turkiye%20gercekleri/turkey%20handbook-tourism.pdf | publisher=The Travel Foundation | access-date=22 July 2008 | archive-url=https://web.archive.org/web/20090225143556/http://www.transanatolie.com/turkce/turkiye/turkiye%20gercekleri/turkey%20handbook-tourism.pdf | archive-date=25 February 2009 }}</ref>

==Notes==<!-- BahamasJSci12:21 -->
{{Reflist|32em}}

==References==
{{Refbegin}}
*{{cite book | last = Harrap | first =Simon |author2=Quinn, David  |title = Tits, Nuthatches and Treecreepers | year = 1996 | publisher = Christopher Helm | isbn = 978-0-7136-3964-3}}
*{{cite book | editor1-last = Snow | editor1-first = David |editor2-last=Perrins|editor2-first=Christopher M. | title = The Birds of the Western Palearctic (BWP) |edition=concise (2 volume) | publisher = Oxford University Press |year = 1998| location =Oxford | isbn = 978-0-19-854099-1 }}
{{Refend}}

==External links==
{{Commons category|Sitta}}

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[[Category:Nuthatches]]
[[Category:Sittidae]]
[[Category:Taxa named by René Lesson]]