Feeding Behavior

Forages mostly by walking on the ground in the open. May associate with cattle or horses in pastures, catching insects flushed from the grass by the grazing animals. Reportedly may sometimes take ticks or insects from backs of cattle.

Eggs

Pale blue-green, unmarked. Number of eggs laid per female is unknown, but may be nearly one egg per day for up to several weeks. When laying eggs, female cowbird may pierce eggs already in nest. Frequent "hosts" for Bronzed Cowbirds include orioles, thrashers, towhees, many others, including smaller birds like warblers and gnatcatchers. Young: Nestling is fed by the "host" parents and develops rapidly, leaves nest 10-12 days after hatching.

Young

Nestling is fed by the "host" parents and develops rapidly, leaves nest 10-12 days after hatching.

Diet

Seeds and insects. Much of annual diet is seeds, including those of grasses and weeds, and waste grain. Occasionally eats berries. Also eats insects, including caterpillars, beetles, flies, and others, plus snails and spiders. While females are laying eggs, snails may be important as a source of calcium.

Nesting

A brood parasite, never raising its own young. In courtship display on ground, male puffs out his feathers so that he appears almost round, spreads and lowers his tail, and points his bill down as he sings; in more intense version, he vibrates his wings and rises slowly a few feet in air, then slowly descends again. Both sexes are promiscuous, not forming pairs. Nest: Builds no nest; eggs are laid in nests of other birds.