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Message: <blockquote data-quote="jmorlan" data-source="post: 1882524" data-attributes="member: 1564">Bill Clark was a speaker last November at the "Central Valley Birding Symposium" where he presented his arguments for splitting: [FONT=Arial,sans-serif]"Harlan's  and Red-tailed Hawks: their taxonomy, differences, and field identification." [/FONT]It was a long paper with a lot of morphological data.  Essentially he was able to show that the supposed hybrids were actually pure Harlan's.  The reaction from the the folks I spoke to, including one member of the AOU Check-List Committee was that they were unconvinced.  One person told Clark that he had made an excellent case that harlani is a good subspecies. Clark had no evidence of assortative mating in areas of contact or overlap which is what the AOU is looking for. My take was that he started his program with the hypothesis that harlani is a good species and then focused on any and all evidence, especially morphological differences which supported his conclusion.  It did not appear to be particularly balanced or objective. I've questioned the maps by Wheeler in "Raptors of Western North America" which show Harlan's overlapping in breeding range with typical Red-tailed.  I corresponded with Wheeler on this, and he has thorough data on these nests, but no satisfying evidence that the birds were correctly identified.  I brought this up during the Q&A after Clark's presentation and he also questions those maps.  What's interesting is that if those maps were correct, they would represent the strongest evidence for harlani as a biological species.  One member of the audience reported an apparent contact zone in British Columbia and Clark seemed interested in following up on that.Clark also argued that krideri was merely a white morph of harlani.   With recent studies of krideri on the breeding grounds by Liguori and Sullivan (cited earlier) that seems unlikely.</blockquote>

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