White Gull identification

[tmanson]

Fellow Fraser Valley birders:

Yesterday, I took some digiscope photos of an almost pure white gull, at the Seabird Island Slough. I have sent these photos to a few birders, who, I know, have considerable gull experience, including those that subscribe to this site I have had some feedback, and one birder is going to forward the photos to gull experts. I won' t say what the id feedback is, because I would like to post the photos to this site. Howerver, being relatively new to digiscoping, I haven't been able to figure out how to post photos to this site, either as an attachment to my e-mail, or to the photo section. I have an I-Mac computer, so the instructions on how to post photos don't seem to work. Any suggestions? Thor

Thor Manson
Hope, B.C.

[Gord]

Thor, send them to me and Ill put them up for you. Macs are something I know little about unless the word 'Big' preceeds it.

[Gord]

This is an odd gull!!! The dark wing-tips are unreal when the rest of the bird has nothing but white! While possibly an albino herring in one shot from head shape (peaked at back?), the big heavy bill and stocky appearance says glaucous-winged as they're similar. But then, the dark wing-tips cant make it pure glaucous-winged. Possibly a hybrid that's mostly albino? (herring x glaucous or...) We know its an adult or soon to be one this summer.

Other ideas?

Here's Thor's pictures.

[tmanson]

Gord: Thanks for posting the pictures. I think your analysis is excellent. Two other very good birders have called it a leucistic Glaucous winged. Both of these birders wanted to forward the pictures on to those with even greater expertise. I compared this gulll to pictures/paintings in Sibley, National Georgraphic, and Olsen, and I couldn't find a Glaucous winged with primaries that dark. They seemed more consistent with Iceland ( Kumlien's ), or Thayer's, but then other characteristics don't fit with these two. A leucistic, Glaucous winged hybrid sounds about right to me. Thor

Thor Manson
Hope B.C.

[Gord]

I looked further into the word 'leucistic' and I see Ive been using abinoism and leucistic improperly. :opps: I only considered something to be 'leucistic' if the plumage is washed out but still discernable (got a good one of a Canada goose Ill share when I find it).

I agree, I dont think it's a pure glaucous-winged based on the wing-tips. Im sure it's crossed with something, but difficult to tell since the mantle is white so we cant tell if it's a dark- backed gull (western) or grey-backed (herring etc) who's involved. But who can say for sure with an interesting specimen like this. One of those things that you'll get a different idea from each person you ask. Let us know what else you learn!

[tmanson]

Fellow Fraser Valley Birders:

As I mentioned before, a very good birder from the Interior wanted to send the pictures of the White Gull on to other " gull experts " The consensus still seems to be leucistic Glaucous winged Gull, but crossed with what because of the darker primaries? The feedback I have just received is the possibility of a Glaucous wingedx Western Gull, and the leucism has caused the primaries to be lighter than what would be expected in a Western Gull. Fun eh?

Thor

Thor Manson
Hope B.C.