sentences:  The brown-headed cowbird is a brood parasite, which places its own eggs in nest of other birds, placing the burden of parenting on other birds.The brown-headed cowbird is thought to have a center of origin in the Great Plains of North America, but has expanded in both directions to spread across most of North America.The behavior of the brown-headed cowbird causes range expansion at the expense of other birds such as warblers, sparrows, and vireos.