Gene Hunn wrote:

>With regard to the Glaucous-winged X Western problem many of we tweets
>have alluded too, what do the bill measurements show re overlap or not of
>Thayer's bills and GW and/or Western bills. My impression is there would
>be no overlap, that is, the largest male Thayer's would still have a
>smaller bill than the smallest female GW and/or Western?


I think you're right, Gene, as Thayer's isn't the next smallest after GW or
Western, so there is probably no overlap between it and the others in size.
It was the fact that some individual birds are hard to place that made me
speculate that Herring x Glaucous-winged hybrids might be filling in that
bill-size gap. A typical adult Herring shouldn't be mistakeable for
anything else, but a Herring X GW hybrid is another story altogether.

And the adults are relatively easy. I have photos of immature gulls on
which I've changed the name several times, other photos on which I've
changed my assessment of the year class, and a few that perhaps will remain
nameless.

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