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Cowbirds and such



Hi folks. I have been amused by the "smoke" war (no flames yet) about Cowbirds; I daresay I might remove a cowbird egg from a Bluebird nest, maybe even a nestling. Some might remember the story of "The Last Bluebird", which died in our clothesline post over 40 years ago and I did not see it, and thought I would never in this life see one. A pair is again nesting in a box in our front yard. There has also been a female Cowbird hanging around. Maybe ought to go check on something, just to make sure... Hmmmmm.
Cowbirds are thought to have evolved in the Great Plains, following the great Buffalo herds, their main source of food, or rather, source of scaring up their food. With this mobile food source, it makes sense that any female that might have had a tendency to "dump" her eggs in a nother's nest would have left far more of her genes, and the tendency to "dump" along with them.
There are other nest parasites in the Eastern US, but I don't think any are "obligate", that is, having to do it. (Cowbirds have no ability to make a nest or care for young.)
With the breaking up of the Eastern forest, the turning of much of the land int pasture, they spread into this "new" habitat, and into bird populations which had no resistance to them.
Shame; they are right interesting, but I don't think I want one in my front yard...
Trees are full of warblers here, but darn if I can ID any of them.


--
Alex Netherton
The Appalachian Naturalist
Asheville, NC
alex@alexnetherton.com
http://alexnetherton.com