Greetings All

There has been a discussion on Frontiers of ID re: Thayer's and Iceland Gull
ID. I
just received this post and thought it might be of interest.

>From Ron Pittaway:

Steve Mlodinow (at bottom) mentioned Thayer's Gulls with pale wingtips near
Port Angeles on Olympic Peninsula in the state of Washington along the
Pacific Coast. I would like to add to this discussion with information
about pale-winged Thayer's on the breeding grounds in Canada.

It is a little known fact that Thayer's Gulls with pale wingtips are found
on the breeding grounds at high latitudes in the Canadian Arctic, such as
near Eureka on Ellesmere Island at 80 degrees north. These Thayer's with
pale wingtips were reported by Parmelee and MacDonald (1960) in Bulletin
169 of the National Museum of Canada. They describe the primary
pigmentation and patterns of nine adult specimens: "The tips of the
primaries (excluding mirrors) grade from dark grey to grey to very light
grey in four males; from very dark grey (nearly black) to grey in four
females. The fifth female has the entire wing tips white or nearly
white..." These and other skins of pale-winged Thayer's are in the Canadian
Museum of Nature (formerly National Museum of Canada). Except for their
paler wingtips, they are otherwise similar to Thayer's and were classified
as Thayer's by the late W. Earl Godfrey. Why are these birds classified as
Thayer's and not Kumlien's? They come from the breeding range of Thayer's
at least 600 miles from Kumlien's on southern Baffin Island. Their darker
mantles and larger measurements (especially the bill) also agree with
Thayer's rather than Kumlien's. There's an illustration of a "pale extreme"
wingtip of Thayer's Gull on page 264 in The Birds of Canada (Godfrey 1986).
These pale-winged Thayer's suggest past introgression with nominate Iceland
or Kumlien's or possibly even Glaucous Gulls. They represent part of the
variability found in Thayer's Gulls.

I did an article on the "Taxonomic History of Thayer's Gull" in the April
1999 issue of Ontario Birds 17(1): 2-13.

Ron Pittaway
Minden Ontario

My original post:
To add to Iceland/Thayer's confusion-
At times, usually in late fall, hundreds of Thayer's Gulls concentrate
near Port Angeles on Washington's Olympic Peninsula. These birds are
roosting, so views of spread wings are limited. However, the folded
wingtip is not-black (varying shades of gray) in 10% or so of these birds.
Some have folded wingtips = in shade to the wing coverts. None of these
birds are paler mantled than the other more typical Thayer's. I think it
unlikely that these are all Thayer's X Iceland Gulls, especially given
that Iceland Gull is very rare in WA. Most likely, these are just part of
the Thayer's Gull spectrum.

Best Wishes
Steven Mlodinow
Everett WA