A West Coast gull mystery…

This time, I am really and truly stumped. This is a case of having taken three pictures and thinking nothing of them (or the species they represented) until I took a good look at them. Now someone like me, who knows what the gull situation is on the west coast (especially when you are looking at large flocks of them), should have known better. But then again, I guess this is why this website exists!

So, here goes the explanation. At first, I thought these were all Glaucus-winged Gulls, a fairly common species out here in greater Vancouver, BC. But upon closer inspection (most especially: the secondaries of all three birds are much too dark, even black), I noticed that none of these gull were pure GWGU!

I will dispose of the “easiest” of the three first: The second bird is certainly in part a GWGU. The only question remaining is what is the other half, Western or Herring Gull? We may never know, but I would welcome any educated guesses!

The first and third birds are not so easy. The first not only has nearly black secondaries, but its bill is much too small to be related in any way to a GWGU or Herring Gull. My best guess is that it is a Thayer’s Gull. The third also looks like a Thayer’s to me, although in this case, I am guessing this is an “old” second year or a “young” third year transitioning to full adulthood. Does anyone have an alternative explanation?

BTW, one final, general comment is in order: I have been told by a few people to be cautious about the black or red stains on the bills, as they are a fairly unreliable way to identify gull species.

Mystery gull no. 1

Mystery gull no. 1

Glaucus-winged Gull hybrid (perhaps with a Western or Western Gull?)

Glaucus-winged Gull hybrid (perhaps with a Western or Western Gull?)

Mystery gull no. 2

Mystery gull no. 2

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