Brown-headed Cowbird
   
A member of the blackbird family, the Brown-headed Cowbird, is distinguished from the other blackbirds by their parasitic nature.  Once called buffalo birds. They were given that name because they would follow the herds of buffalo that roamed the plains of North America and feed on the insects stirred up by the moving buffalo.  Because the birds were always on the move, they didn't have time to build nests and stay in one location to rear their offspring.

Instead, they adapted the method of brood parasitism to ensure their survival.  In practice the female deposits one or two eggs in the nests of other, usually smaller, bird species.  Infant cowbirds simply out-compete their nest mates.  They were called cowbirds when they switched to domesticated cattle, as the number of buffalo decreased.  

The egg of the Brown-headed Cowbird is white, bluish or greenish with a fine speckling of reddish brown. In this photo, the cowbird chick is in the process of hatching. Cowbird chicks usually hatch a day or two before the eggs of the host bird and grow rapidly, giving them a competitive head start.

Buffalo Bird