There are three types of cowbirds in North America. The Brown-headed Cowbird is found throughout the continent right up to the conifer regions of the North.
The Bronzed Cowbird is found along the borders of the southern states down into Mexico, and the Shiny Cowbird, which is fairly new to North America is showing up more and more in the State of Florida.
Cowbirds are brood parasites, where the female cowbird will lay her eggs in the nest of other bird species. These eggs are then abandoned by the cowbirds, leaving them to be hatched and the young cowbirds to be raised by the unknown parent birds of the nest. The young cowbirds are more aggressive than the parents own young and these young cowbirds will push the young of the parent birds from the nest to perish, ensuring they will get all the food to survive.