Tuesday, July 29, 2014

Red-tailed Hawk

At the Mission Nature Park and Bike Trail on 23 February, when we spied this raptor, we thought we found our quarry, a Hook-billed Kite. It seemed russet-breasted and slender. But closer examination of my photos proved this to be a western Red-tailed Hawk adult, intermediate between light and dark morphs. I had never before observed this plumage.
This Red-tailed Hawk race breeds across most of western Canada. Some individuals are dark, others pale, and some intermediate, with still others intermediate between these three morphs. Why do Red-tailed Hawks come in different color phases? One hypothesis is that prey species learn to identify what a Red-tailed Hawk should appear. This learning makes the prey vulnerable when a different morph appears. If the odd morph becomes more common, due to its hunting success, then the prey learns the new plumage patterns, and another morph will be favored.

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