I've seen this bird increasingly in town where I used to see starlings. Are they expanding?

asked by Shenandoah McGuire almost 7 years ago
  • 1 Answer
Dave Irons
1. by Dave Irons on September 04, 2013 at 11:41 pm
Brown-headed Cowbirds have expanded their range significantly in concert with caucasian settlement of North America. Wherever you find the footprint of non-native peoples, you will find cowbirds. Cowbirds do not inhabit contiguous forest, thus the unfragmented pre-columbian forests of eastern and western North America were a barrier to this species, whose range was restricted to the prairie regions in the central part of the continent. As forests were cleared for agriculture, the resulting pathways and edge habitats allowed the Brown-headed Cowbird to expand coast to coast. On some level, this expansion is still going on. Modern forest practices, most notably clear-cutting, have accelerated the creation of cowbird-friendly landscapes and made many more species vulnerable to their nest parasitism.