Hi Tweets,

Gene Hunn writes:

>There was also a Pseudo-Glaucous Gull, with a very nice two-toned pink and
>dusky bill, very pale body, but dusky gray primaries and tail. A very worn
>and bleached 2nd winter Glaucous-winged, I would surmise.

The presence of actual pink or flesh rather than the muddier tone of a
Glaucous-winged Gull (Larus glaucescens) in the basal portion of the bill
could argue with some persuasiveness a Glaucous (L. hyperboreus) component
to the parentage. Perhaps a better indicator might be the extent of the
distal black tip.

At the age when an immature Glaucous-winged and Glaucous resemble each
other, the amount of distal black should be quite different--in
Glaucous-winged, the distal half or better of the bill; in Glaucous, the
distal one-quarter.

>In any case, I am more than ever puzzled about Slaty-backed identification.
>Based on the one bird whose foto is now posted, observers are assuming that
>a definitive feature of Slaty-backed Gull is a "Thayer's-like" bill, but the
>fotos in Grant suggested otherwise, i.e., that the typical Slaty-backed has
>a bill at least as strong as a local Herring Gull, if slighter at least than
>the heavy extremes of Western and Glaucous-wingeds.

Perhaps it's a female bird at the small extreme. Remember Kaufman writing
about Thayer's ID, that the ones we think of as 'typical' Thayer's Gull (L.
thayeri)--i.e., small bill, very round head--are likely the females, with
the males robust enough to be mis-ID'ed as possible Thayer's X ? hybrids.

>There are either a number of
>Slaty-backed Gulls slipping through without being identified because they
>are not "typical," or Western Gull's can show a much wider range of eye
>colors, winter head patterns, wing-tip patterns, etc., than I have assumed.

Agree with the first part, not sure I would fully concur with the second.

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)