Forest and Rangeland Birds of the United States

Natural History and Habitat Use

Brown-headed Cowbird -- Molothrus ater


RANGE: Breeds from southeastern Alaska, northern British Columbia, and southern Mackenzie east to southern Quebec and southern Newfoundland, and south to Mexico, the Gulf Coast, and central Florida. Winters from northern California, central Arizona, the Great Lakes region, and New England south to Mexico, the Gulf Coast, and southern Florida.

STATUS: Common.

HABITAT: Prefers habitats where low or scattered trees are interspersed with grassland vegetation. Originally occupied open grasslands and avoided unbroken forestlands, but due to agriculture, cattle grazing, and deforestation, occupies a much expanded range. Now found in open coniferous and deciduous woodlands, forest edges, brushy thickets, agricultural land, and suburban areas.

SPECIAL HABITAT REQUIREMENTS: Habitats with open grassy spaces.

NEST: Builds no nest; lays its eggs in the nests of over 100 species of birds, particularly tyrant flycatchers, finches, vireos, and warblers.

FOOD: Gleans weed seeds, which form over half of the diet, as well as grass seeds, waste grain, and insects from the ground. Commonly forages in pastures searching for insects stirred up by cattle.

REFERENCES: Beal 1900, Bent 1958, DeGraff et al. 1980, Forbush and May 1955, Johnsgard 1979, Mayfield 1965.


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