Nests are made in cavities, including openings in buildings, hanging plants, and other cup-shaped outdoor decorations. Sometimes nests abandoned by other birds are used. Nests may be re-used for subsequent broods or in following years. The nest is built by the female, sometimes in as little as two days. It is well made of twigs and debris, forming a cup shape, usually 1.8 to 2.7 m (5.9 to 8.9 ft) above the ground.
Brown-headed Cowbirds (Fam.)
The species lives in open or semi-open country and often travels in flocks, sometimes mixed with red-winged blackbirds (particularly in spring) and bobolinks (particularly in fall), as well as common grackles or European starlings. These birds forage on the ground, often following grazing animals such as horses and cows to catch insects stirred up by the larger animals. They mainly eat seeds and insects.
Before European settlement, the brown-headed cowbird followed bison herds across the prairies. Its population expanded with the clearing of forested areas and the introduction of new grazing animals by settlers across North America. Brown-headed cowbirds are now commonly seen at suburban birdfeeders.