Tuesday, June 18, 2013

Common Grackle

Previously I blogged about the beauty of Common Grackles. I suspect you would agree with me about the beauty of this species if I told you that this photo is of a rare bird-of-paradise—but it is not, just a grackle.

One of my mentors, Alan Phillips, was fond of quoting “if ever I am accused of destroying the crops, I certainly would want an ornithologist to defend me.” Nevertheless, Common Grackles are “now among the most significant agricultural pest species in North America, causing millions of dollars in damage to sprouting corn.”  Not only that, they eat bird eggs and nestlings, and even other adult birds. If that reputation was not enough, grackles may carry the fungus that causes histoplasmosis, a respiratory disease that can be fatal to people. Grackle roosts are often sprayed with detergents which wash off the protective oils on bird feathers, leaving the grackles damp and vulnerable to exposure. Perhaps due to these and other control measures, at least in the East, grackle populations are in decline (perhaps as much as by 30% between 1966 and 1993). Western populations, however, are increasing and spreading westward. Most of this information and the second quote are from Peer and Bollinger 1997).

I took this grackle photo of a bird being banded in Northfield, Minnesota. At the time I did not notice the small arthropod on its lower mandible—no idea what the creature might be.

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