[Tweeters] Re: Crossbills

Mike Patterson celata at pacifier.com
Wed Jun 8 10:14:04 PDT 2005

There are 9 to 9 North American subspecies of Red Crossbill
(depending on how you do the math) plus White-winged Crossbill
which means up to 10 "kinds" of crossbills in North America
(Eurasian has at least 3 more). Sibley's lays them all out.

Jeffrey Groth advocates splitting them all (see:
http://research.amnh.org/ornithology/crossbills/diagnosis.html )

The most diagnostic way to sort them is by vocalizations. Overall
size, bill size and color work to a lesser degree and require
considerable practice with all forms. The way the bill crosses
is not considered a taxonomically significant character.

I doubt that the AOU will split all forms. The very large "Mexican"
Crossbill (type 6) is the most likely split and the very small "Sitka"
Crossbill (type 3) is a fair bet. The stuff in the middle is squishier,
and if one of these gets split all would pretty much have to be

Mike Patterson
Astoria, OR
celata at pacifier.com

Go, and sin no more (ethics in birding)

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