ambience: cowbird chatter
It’s a great biological mystery: when a bird is reared by a whole other species, how does it find its way back to mate with its own kind? I’m Jim Metzner, and this is the Pulse of the Planet. We’re listening to the chattering of cowbirds, a species that faces just this dilemma. Mark Hauber is a behavioral ecologist at Cornell University.
“The brown-headed cowbird is one of the common birds around the whole of North America, and it belongs to one percent of all bird species in the world that does not care for its young. They do not build a nest, they do not incubate their eggs and they do not feed their young. What they do is they lay their eggs in other speciesâ€™ nests, and they leave it to the other species, called the host species, to raise their young.”
This means that cowbird babies are not exposed to adults of their species at what’s thought to be critical points of development.
“One of the major questions is how a young cowbird knows that itâ€™s a cowbird. When the cowbird young becomes independent it starts socializing with other cowbirds even though itâ€™s never been exposed to adult or juvenile cowbirds in the nest or early on during its life. It is really important for cowbirds to recognize other cowbirds. The most important reason, is that they reproduce by the mating of male and female cowbirds and if you do not recognize your own species you will not produce fertile offspring. Itâ€™s that easy. The second reason why cowbirds need to recognize their own species is that they are highly social animals. They live and forage in theses large flocks of cowbirds.”
Dr. Hauber believes that the chattering you’re listening to holds the key to species recognition. We’ll hear more about his research on future programs.
Pulse of the Planet is presented with support provided by the National Science Foundation. I’m Jim Metzner.