Monday Morning Birdwalk
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The Cowbird story is one of the more absorbing of North American bird lore. Early settlers noticed Cowbirds congregated around herds of Bison. However, there was never evidence of nests where these birds laid their eggs and raised their young. Early ornithologists determined that since the Bison herds were semi-nomadic, the Cowbirds travelled with the herds. This life made no provisions for standard nesting habits. It became apparent that the Cowbirds were laying their eggs in the nests of other birds, and leaving the hatching and rearing of their young to these adopted bird parents while they followed the Bison herds roaming the prairie.
The question that occurs to me is, how does the Cowbird, raised by some other species, know it is a Cowbird, and adopts the correct behavior, vocalizations, and mates? There have been studies of brood parasitism with this question in mind. In laboratory experiments, Cowbirds and other brood parasites that spend too much time with their foster families end up learning their host species’ songs, picking up their behaviors, and attempting to mate with them. In the wild, though, they’re somehow able to resist this. By the time they’re about a month old, they’ve learned to act like Cowbirds, and they know to mate with their own species. If the true parents have abandoned the eggs and chicks, how is this conditioning taking place?
In our next quarterly newsletter, we’ll talk some more about bird parasitism and how the adopted species survives.
The Monday Morning Bird Walk has been a weekly event at Huntley Meadows Park since 1985. It takes place every week, rain or shine (except during elec- trical storms, strong winds, or icy trails), at 7AM (8AM from November through March), is free of charge, requires no reservation, and is open to all. Birders meet in the parking lot at the Park's en- trance at 3701 Lockheed Blvd, Alexandria, VA. Questions should be directed to Park staff during normal business hours at (703)768 - 2525.