/kow"berrd'/, n.any of several New World blackbirds of the genus Molothrus, esp. M. ater, of North America, that accompany herds of cattle.[1795-1805, Amer.; COW1 + BIRD]
* * *Any of six passerine species related to New World blackbirds (family Icteridae) that exhibit brood parasitism.Cowbirds lay their eggs in the nests of other birds, usually one to each host nest. Young cowbirds, which displace nestlings or outcompete them for food, may grow larger than the foster parents. In parts of North America, the brown-headed cowbird (Molothrus ater) parasitizes the nests of more than 200 other bird species; others use the nests of only one or two kinds of oriole. Cowbirds forage on the ground, often associating with cattle in order to catch insects stirred up by the cows' hooves. The male of most species is a uniform glossy black, the female grayish brown.
* * *▪ birdany of five species of birds (bird) that belong to the family Icteridae (order Passeriformes (passeriform)) that are named for their habit of associating with cattle in order to prey upon insects (insect) stirred up from vegetation. Cowbirds forage on the ground. In most species the male cowbird is uniform glossy black in colour, while the female is grayish brown. Cowbirds are parasitic (parasitism) egg layers; that is, they habitually lay their eggs in the nests (nest) of other birds. Young cowbirds, usually one to the host nest, customarily either displace competing nestlings or appropriate their food. They may even exceed the foster parents in size. Some species parasitize many kinds of birds, but others use the nests of only one or two kinds of orioles (oriole).Best known is the brown-headed cowbird (Molothrus ater) of temperate North America, which once followed bison herds and fed on the grasshoppers (grasshopper) that they flushed from the Great Plains. Since the great bison herds were exterminated and replaced by cattle, M. ater has followed cattle, and it now ranges from coast to coast. Its parasitic habits have contributed to the declines of other songbirds (songbird). Females may lay one egg per day for several weeks—up to 40 in a single season—often after removing one from the host nest. They have been known to lay eggs in the nests of more than 200 species of birds, of which 140 species are known to have raised nestling cowbirds at the expense of their own young.Sy Montgomery
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