Subject: [Tweeters] Question about Color Morphs in Buteos
Date: Nov 16 17:57:18 2011
From: ixoreus at - ixoreus at


A quick look Ferguson-Lees and Chrisities' massive Raptors of the World
shows 28 species worldwide in genus Buteo, of which 15 have light and dark
color morphs. The same book notes that there are at least a dozen reasons
set out by scientists for dark/light color morphs in animals, but that for
raptors a likely explanation could be frequency-dependent selection: that
"potential prey will less easily learn to evade a predator that appears in
different guises."

By the way, the author cited for this thesis in a 1973 article in the
journal Evolution is none other than Dennis Paulson, then affiliated with
Burke Museum and U. of Washington.

Bob Sundstrom

> Does anyone out there know of any research or references discussing the
> occurrence of the different color morphs found in Buteos?? How extensive
> is this within the genus--does it occur in Eurasian or African species??
> What is known about the genetics behind this??
> This last week I've seen very dark and very light Rough-legs in Walla
> Walla County, and been shown pictures of a very light red-tail.? I've also
> previously seen both extremes of Swainson's Hawk around here.? This has
> just made wonder what's known about this.
> Chad Merkley
> Richland, WA
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