Cowbird

Cowbird
Female brown-headed cowbird
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Passeriformes
Family:	Icteridae
Genus:	Molothrus Swainson, 1832
Species
M. rufoaxillaris M. oryzivorus M. aeneus M. bonariensis M. ater

Cowbirds are birds belonging to the genus Molothrus in the family Icteridae. They are brood parasitic New World birds which are unrelated to the Old World cuckoos, one of which, the common cuckoo, is the most famous brood parasitic bird.

The Molothrus genus contains:

• Screaming cowbird, Molothrus rufoaxillaris
• Giant cowbird, Molothrus oryzivorus (formerly in Scaphidura)
• Bronzed cowbird, Molothrus aeneus
• Shiny cowbird, Molothrus bonariensis
• Brown-headed cowbird, Molothrus ater

The non-brood parasitic baywing was formerly placed in this genus; it is now classified as Agelaioides badius.

Behavior

These birds feed on insects, including the large numbers that may be stirred up by cattle. In order for the birds to remain mobile and stay with the herd, they have adapted by laying their eggs in other birds' nests. The cowbird will watch for when its host lays eggs, and when the nest is left unattended, the female will come in and lay its own eggs. The female cowbird may continue to observe the nest after laying her eggs. If the cowbird egg is removed, the female cowbird may destroy the host's eggs (see "Mafia hypothesis" for an explanation of this behavior).^[1]

References

1. Jeffrey P. Hoover; Scott K. Robinson (13 March 2007). "Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs". Proceedings of the National Academy of Sciences. Retrieved 26 August 2009.

• Jaramillo and Burke, New World Blackbirds ISBN 0-7136-4333-1

External links

• The White Laboratory of Animal Behavior, University of Pennsylvania
• Icterid (including cowbirds) videos, photos and sounds on the Internet Bird Collection
• Audubon Society: Cowbirds and Conservation
• Juvenile Brown-headed Cowbird with host/parent dark-eyed Junco