Glaucous-winged and Western Gulls are clearly ecological counterparts and
even if they aren't each others closest relative they are still closely
related and therefore well situated to hybridize in their contact zone. Keep
in mind that Glaucous-winged Gulls also hybridize with Herring and Glaucous
Gulls - perhaps fairly commonly as I understand some of the emerging thought
on this.

Charles.

--
Charles Swift
Moscow, ID
chaetura at gmail.com
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