Cowbird

Cowbird
Female brown-headed cowbird
Scientific classification
Domain:	Eukaryota
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 of New World origin. They are brood parasites, laying their eggs in the nests of other species.

The genus Molothrus contains:

Image	Scientific name	Common Name	Distribution
	Molothrus rufoaxillaris	Screaming cowbird	north east and central Argentina, south east Bolivia, central Brazil and throughout Paraguay and Uruguay
	Molothrus oryzivorus (formerly in Scaphidura)	Giant cowbird	southern Mexico south to northern Argentina, and on Trinidad and Tobago
	Molothrus aeneus	Bronzed cowbird	southern U.S. states of California, Arizona, New Mexico, Texas, and Louisiana south through Central America to Panama
	Molothrus bonariensis	Shiny cowbird	South America
	Molothrus ater	Brown-headed cowbird	southern United States and Mexico

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

Behavior

Further information: Brood parasite

Cowbirds eat 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 eggs. If the cowbird egg is removed, the female cowbird may destroy the host's eggs to dissuade further removals, according to the Mafia hypothesis.

References

• 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