Brown-headed Cowbird - Photos by Bruce Dayton - Brown-headed Cowbird (Molothrus ater)

ORDER: Passeriformes
FAMILY: Icteridae (Blackbirds and Orioles - 23 Species)
SPECIES: Brown-headed Cowbird (Molothrus ater)

Brown-headed Cowbird
The Brown-headed Cowbird is one of two species of cowbirds (the other is the Bronzed Cowbird) found in North America. Both species are brood parasites that lay their eggs in the nests of other birds. The fragmentation of forest habitats in North America has resulted in a great increase in the edge habitats favored by cowbirds. Cowbird parasitism may be one cause in the general decrease in numbers of songbirds in North America. The cowbird gets its name from its close association with livestock, such as horses and cattle, which disturb insects on the ground when feeding. Their parasitic nesting behavior complements their nomadic lifestyle. They lay eggs in other nests, then they move on searching for food. The cowbird eats many insects which are pests to humans.
SIZE	The Brown-headed Cowbird is 6-8 inches.
DESCRIPTION	The Brown-headed Cowbird has dark eyes and a short, conical (finch-like) bill suitable for its diet of insects, (especially grasshoppers) seeds and berries. The adult male has an iridescent black body and a coffee-brown head, which makes it easy to identify while in the field. The adult female is slightly smaller than the male and uniformly brownish-gray with a pale throat and fine streaking on the underparts.
NESTING	The Brown-headed Cowbird is a brood parasite, it does not build a nest of its own. The female lays her eggs in the nests of other bird species. The host parents then raise the cowbird chick as their own. The cowbird's egg usually hatches a little before the host's eggs which give the cowbird chick a head start over the host's chicks. Many host species such as the Song Sparrow do not distinguish between their own eggs and those of the cowbird. Female cowbirds have a long reproductive period and can lay as many as 40-80 eggs over a two month period. The smallest recorded host of cowbird young is the small Brown Creeper, while the largest host is the Meadowlark.
RANGE	The Brown-headed Cowbird's breeding range runs from southeastern Alaska, through southern Canada, through the entire continental U.S. to central Mexico. The northern flocks migrate in winter to the southern part of their range, including southern Mexico and Florida. Some Brown-headed Cowbirds are permanent residents in the southern parts of their range.
HABITAT	Cowbirds prefer habitats with low or scattered trees among grassland vegetation, such as woodland edges, orchards, thickets, prairies and pastures.
DIET	Their main food items are seeds and insects, such as beetles and grasshoppers. They can often be seen in pastures, feeding on the insects that are stirred up by the movement of horses and cattle.




Brown-headed Cowbird

Groton Township Tompkins County, New York


BhCb_357T_053173	BhCb_357T_053178


BhCb_357T_053230


Female	Male