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Thursday, 26 January 2012


Anticipating the usual flood of Kumlien's-like gulls in the west and Thayer's-like gulls in the east, I've put together a proposed thayeri-kumlieni-glaucoides scoring system at

It's a first draft cut to develop some consensus about how we talk about and evaluate these things. Feedback is welcome. (I've already got ideas to improve it, but I want to hear more ideas.)

Basically, it's a 4-point scale:

0 = glaucoides
1 = in between
2 = kumlieni
3 = in between
4 = thayeri

evaluating 7 different features of first cycle birds. So a maximum score of 28 is a classic Thayer's, while a minimum score of 0 is a perfect nominate glaucoides. The key caveat is at the end: "even if we come up with a formula that satisfies most birders, there's still no guarantee we would be accurately placing birds in the correct category until further research, ideally tracking birds from the breeding grounds to the wintering grounds, is done."

Steve Hampton, Ph.D.