Cowbird

2025-07-04T12:58:01Z

2601:249:8380:5EB0:BCA7:5E3D:D6D7:7A8D: /* Behavior */

{{Short description|Genus of birds}}
{{Automatic taxobox
| image = Brown headed cowbird female in JBWR (25487).jpg
| image_caption = Female brown-headed cowbird
| taxon = Molothrus
| authority = [[William Swainson|Swainson]], 1832
| type_species = ''[[Brown-headed cowbird|Fringilla pecoris]]''<ref name=HM4>{{cite web |url= https://www.aviansystematics.org/4th-edition-checklist?viewfamilies=199 |title= Icteridae |author= |date= |website= aviansystematics.org |publisher= The Trust for Avian Systematics |access-date= 2023-07-16}}</ref>
| type_species_authority = [[Johann Friedrich Gmelin|Gmelin, JF]], 1789
| subdivision_ranks = Species
| subdivision = * ''[[Screaming cowbird|M. rufoaxillaris]]''
* ''[[Giant cowbird|M. oryzivorus]]''
* ''[[Shiny cowbird|M. bonariensis]]''
* ''[[Bronzed cowbird|M. aeneus]]''
* ''[[Bronze-brown cowbird|M. armenti]]''
* ''[[Brown-headed cowbird|M. ater]]''
}}

'''Cowbirds''' are [[bird]]s belonging to the [[genus]] '''''Molothrus''''' in the [[Family (biology)|family]] [[Icteridae]]. They are of [[New World]] origin, but some species not native to North America are invasive there, and are obligate [[brood parasite]]s, laying their eggs in the nests of other species.

The genus was introduced by English naturalist [[William Swainson]] in 1832 with the [[brown-headed cowbird]] (''Molothrus ater'') as the [[type species]].<ref>{{ cite book | last1=Swainson | first1=William | author1-link=William Swainson | last2=Richardson | first2=J. | author2-link=John Richardson (naturalist) | year=1831 | title=Fauna boreali-americana, or, The zoology of the northern parts of British America | volume=Part 2. The Birds | publisher=J. Murray | place=London | page=277 | url=https://biodiversitylibrary.org/page/41549684 }} The title page bears the year 1831 but the volume did not appear until 1832.</ref><ref>{{ cite book | editor-last=Paynter | editor-first=Raymond A. Jr | year=1968 | title=Check-list of Birds of the World | volume=14 | publisher=Museum of Comparative Zoology | place=Cambridge, Massachusetts | page=195 | url=https://biodiversitylibrary.org/page/14481396 }}</ref> The genus name combines the [[Ancient Greek]] {{Transliteration|grc|mōlos}}, meaning "struggle" or "battle", with {{Transliteration|grc|thrōskō}}, meaning "to sire" or "to impregnate".<ref>{{cite book | last=Jobling | first=James A. | year=2010| title=The Helm Dictionary of Scientific Bird Names | url=https://archive.org/details/helmdictionarysc00jobl_997 | url-access=limited | publisher=Christopher Helm | location=London | isbn=978-1-4081-2501-4 | page=[https://archive.org/details/helmdictionarysc00jobl_997/page/n258 258] }}</ref> The English name "cowbird", first recorded in 1839, refers to this species often being seen near cattle.<ref name=OED>{{Cite OED | Cowbird}}</ref>

==Species==
The genus contains six species:<ref name=IOC>{{cite web |url=http://www.worldbirdnames.org/ |title=IOC World Bird List (v 10.2) |last1=Gill |first1= F. |last2=Donsker|first2=D.|last3=Rasmussen |first3=P. |date=July 2020 |access-date=July 15, 2020 }}</ref>
{{Species table |genus= Molothrus |authority-name=[[William Swainson|Swainson]] |authority-year=1832 |species-count=six|no-note=y|narrow-percent=75}}

{{Species table/row
|name=Screaming cowbird |binomial=[[Molothrus rufoaxillaris]]
|image=File:Screaming Cowbird (Molothrus rufoaxillaris).jpg|image-size=180px |image-alt=
|authority-name=Cassin |authority-year=1866 |authority-not-original=
|range= Northeast and central Argentina, southeast Bolivia, central Brazil and throughout Paraguay and Uruguay
|range-image=File:Molothrus rufoaxillaris map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies=
}}

{{Species table/row
|name= Giant cowbird|binomial=[[Molothrus oryzivorus]]
|image=File:Giant Cowbird - Pantanal - Brazil H8O0545 (23593619780).jpg|image-size=180px |image-alt=
|authority-name=Gmelin, JF |authority-year=1788 |authority-not-original=yes
|range= Southern Mexico south to northern Argentina, and on Trinidad and Tobago
|range-image=File:Molothrus oryzivorus map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies={{Collapsible list |expand=yes |title=Two subspecies |bullets=on
| ''M. o. impacifus'' ([[James L. Peters|Peters, JL]], 1929)
| ''M. o. oryzivorus'' ([[Johann Friedrich Gmelin|Gmelin, JF]], 1788)
}}
}}

{{Species table/row
|name=Shiny cowbird |binomial=[[Molothrus bonariensis]]
|image=File:Shiny cowbird (Molothrus bonariensis) male.JPG|image-size=180px |image-alt=|image-caption=Male
|image2 =File:Molothrus bonariensis Chamón común Shiny Cowbird (female) (8348449535).jpg|image2-caption=Female
|authority-name=Gmelin, JF |authority-year=1789 |authority-not-original=yes
|range= South America, the Caribbean, and Florida
|range-image=File:Molothrus bonariensis map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies={{Collapsible list |expand=yes |title=Seven subspecies |bullets=on
| ''M. b. minimus'' Dalmas, 1900
| ''M. b. cabanisii'' [[John Cassin|Cassin]], 1866
| ''M. b. venezuelensis'' [[Witmer Stone|Stone]], 1891
| ''M. b. aequatorialis'' [[Frank Chapman (ornithologist)|Chapman]], 1915
| ''M. b. occidentalis'' [[Hans von Berlepsch|Berlepsch]] & [[Jan Sztolcman|Stolzmann]], 1892
| ''M. b. riparius'' [[Ludlow Griscom|Griscom]] & [[James Greenway|Greenway]], 1937
| ''M. b. bonariensis'' ([[Johann Friedrich Gmelin|Gmelin, JF]], 1789)
}}
}}

{{Species table/row
|name=Bronzed cowbird |binomial=[[Molothrus aeneus]]
|image=File:Bronzed Cowbird (Molothrus aeneus) (7223072934).jpg|image-size=180px |image-alt=
|authority-name=Wagler|authority-year= 1829|authority-not-original=yes
|range= Southern U.S. states of California, Arizona, New Mexico, Texas, and Louisiana south through Central America to Panama
|range-image=File:Molothrus aeneus map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies={{Collapsible list |expand=yes |title=Three subspecies |bullets=on
| ''M. a. loyei'' Parkes & Blake, 1965
| ''M. a. assimilis'' ([[Edward William Nelson|Nelson]], 1900)
| ''M. a. aeneus'' ([[Johann Georg Wagler|Wagler]], 1829)
}}
}}

{{Species table/row
|name= Bronze-brown cowbird|binomial=[[Molothrus armenti]]
|image=|image-size=180px |image-alt=
|authority-name=Cabanis |authority-year=1851 |authority-not-original=yes
|range= Colombia
|range-image=File:Molothrus armenti map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= NT
|population=
|direction=
|subspecies=
}}

{{Species table/row
|name= Brown-headed cowbird|binomial=[[Molothrus ater]]
|image=File:Molothrus ater 2.jpg|image-size=180px |image-alt=|image-caption=Male
|image2 =File:Brown headed cowbird female in JBWR (25490).jpg|image2-caption=Female
|authority-name=Boddaert |authority-year=1783 |authority-not-original=yes
|range= Southern Canada, United States, and Mexico
|range-image=File:Molothus ater Map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies={{Collapsible list |expand=yes |title=Three subspecies |bullets=on
| ''M. a. artemisiae'' [[Joseph Grinnell|Grinnell]], 1909
| ''M. a. obscurus'' ([[Johann Friedrich Gmelin|Gmelin, JF]], 1789)
| ''M. a. ater'' ([[Pieter Boddaert|Boddaert]], 1783)
}}
}}
{{Species table/end}}

One [[Extinction|extinct]] species, ''[[Molothrus resinosus]]'', is known from [[fossil]] remains recovered from the [[Talara Tar Seeps]] of northwestern [[Peru]], and likely went extinct during the [[late Quaternary]]. It may have been a close associate of [[Pleistocene megafauna]] communities, and may have gone extinct following their collapse in populations.<ref>{{Cite journal|last1=Steadman|first1=David W.|last2=Oswald|first2=Jessica A.|date=July 2020|title=New species of troupial (''Icterus'') and cowbird (''Molothrus'') from ice-age Peru|url=https://bioone.org/journals/the-wilson-journal-of-ornithology/volume-132/issue-1/1559-4491-132.1.91/New-species-of-troupial-Icterus-and-cowbird-Molothrus-from-ice/10.1676/1559-4491-132.1.91.full|journal=The Wilson Journal of Ornithology|volume=132|issue=1|pages=91–103|doi=10.1676/1559-4491-132.1.91|s2cid=220714575 |url-access=subscription}}</ref> The [[convex-billed cowbird]] (''Pandanaris convexa'') is another extinct species that likely co-evolved with the megafauna, though it is placed in its own genus.

The nonparasitic [[baywing]]s were formerly placed in this genus; they are now classified as ''Agelaioides''.

== Behavior ==
Cowbirds eat mostly insects and seeds. Some species follow [[ungulate]]s to catch insects stirred up by the larger animals' grazing.

Cowbirds reproduce by laying their eggs in other birds' nests. Female cowbirds observe a potential host bird laying its eggs, and when the nest is left momentarily unattended, the cowbird lays its own egg in it. The female cowbird may continue to observe this nest after laying eggs. Some bird species have evolved the ability to detect such parasitic eggs, and may reject them by pushing them out of their nests, but female cowbirds have been observed to attack and destroy the remaining eggs of such birds in retaliation, as suggested by the [[Mafia hypothesis]].<ref>{{cite journal| author = Jeffrey P. Hoover |author2=Scott K. Robinson | title = Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs | journal = Proceedings of the National Academy of Sciences | date = 13 March 2007 |volume=104 |issue=11 |pages=4479–4483 |doi=10.1073/pnas.0609710104 |doi-access=free |pmid=17360549 |pmc=1838626 |bibcode=2007PNAS..104.4479H }}</ref>

==References==
{{Reflist}}

== Further reading ==
* Jaramillo and Burke, ''New World Blackbirds'' {{ISBN|0-7136-4333-1}}

==External links==
{{NSRW Poster}}
* [https://web.archive.org/web/20081130205441/http://www.audubon.org/bird/research/ Audubon Society: Cowbirds and Conservation]

{{Brood parasite}}
{{Passeroidea|I.|state=collapsed}}
{{Taxonbar|from=Q1137414}}
{{Authority control}}

[[Category:Brood parasites]]
[[Category:Cowbirds| ]]
[[Category:Birds of North America]]
[[Category:Bird genera]]
[[Category:Taxa named by William Swainson]]

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Cowbird