The common pigeons that abound in our cities have a variety of colors, which would seem to indicate that color isn't important to their survival. That may be about to change, though, as Peregrine Falcon numbers recover to historic levels. Recent observations and experiments strongly suggest that one color pattern, that of generally blue-gray plumage with a prominent white rump, is protective against high-speed diving attacks by predators. The Peregrine Falcon may reach speeds of over 350 miles per hour in such an attack dive, and about the only defense a pigeon has is an evasive roll just before impact can occur.
Pigeons with the white rump feathers evaded falcon attacks much more often than pigeons lacking such a patch. When rump feathers were switched between the two plumage types, the survival figures likewise switched, strongly indicating that it was the white rump that made the difference in survival. The experimenters suggested that falcons fixating on the prominent patch miss the wing movements that signal the beginning of evasive action, and thus were unable to correct for it.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
Palleroni, A., C. T. Miller, M. Hauser, and P. Marler. 2005. Prey plumage adaptation against falcon attack. Nature 434:973-974.