In response to Skip Russell's posting, I actually mentioned that hybrid
*glaucous-winged* x glaucous gulls seemed smaller than glaucous to me, not
herring x glaucous (which should, of course, also look smaller than
glaucous). I haven't seen what I was convinced was a glaucous x herring
hybrid, including in Chukotka where Siberian herring and glaucous breed in
the same areas commonly. I think they don't overlap a whole lot in Alaska
(at least not as much as glaucous and glaucous-winged or herring and
glaucous-winged), but they certainly do overlap, both there and in Canada,
and hybrids have been reported on the Pacific coast. I'd love to see a
photo of what someone considered such a hybrid in this area.

As far as size variation in glaucous, I know the species varies a lot, but
I'm not sure the last word has been said about that variation. Dwight, in
Gulls of the World (Amer. Mus. Nat. Hist. Bull. 52, 1925), argued against
recognizing Larus hyperboreus barrovianus as a western subspecies of this
species, stating there just wasn't that much difference. So the size
variation may be individual rather than geographic. I don't have my copy of
Cramp & Simmons, Birds of the Western Palearctic, here to double check the
subspecies thing. But I must say that the glaucous gulls I've seen at
close range here usually (always?) looked larger to me than any of the
other species in the area.

And I was remiss before by not mentioning *the* book for gull
identification, for tweeters who don't know it. Grant, P. J. 1986.
Gulls: a guide to identification. T. & A. D. Poyser, Calton, England. If
you buy this book, be sure it is the second edition, which includes our
west coast gulls.

Dennis Paulson phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416