Skip Russell wrote:

"I didn't realize that Herring and Glaucous-winged overlapped so much. Are
hybrids of this type known?"

Yes, Sam Patten discovered a hybridizing population in southern Alaska,
collected specimens there (some are in the National Museum of Natural
History, others in the Burke Museum; I've got photos of the specimens) and
wrote about them. The reference: Patten, S., and A. R. Weisbrod. 1974.
Sympatry and interbreeding of Herring and Glaucous-winged gulls in
southeastern Alaska. Condor 76: 343-344. I don't think anything else has
been written about them.

We have three adult gulls in the Slater Museum that look essentially like
Herrings but with maybe a hint of gray in the black wingtips; the
underwingtips are a bit paler(!). All had brown eyes, or yellow eyes
heavily flecked with brown. They are emphatically not GWGU x WEGU hybrids.
They are clearly too big for Thayer's, and all we can make of them is that
they are Herring x Glaucous-winged hybrids. All are from Puget Sound in
winter.

I've never seen a gull like the birds you described, Skip, and I would love
to see photos of them. Come up any time with your bucket of slides, but
let me know in advance so I can bring mine from Seattle. I think I have
about 1500 gull photos now. A few other people here have spent a lot of
time photographing gulls, too. We could sure put out a supplement to
Grant's book!

By the way, Tweeters, I'm off on vacation until 3 January. I may check my
mail next week, but I'm not sure. I'll miss you all, but I hope you have a
great holiday season and that you're out there tweeting!

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