Last night, I was going through some photos that I took over the past few days. Travis, looking over my shoulder as he is wont to do, pointed at photo of a gull and said "Thayer's Gull Dad." He was, correct, it was a Thayer's, which makes me very proud. He noted the tips of the primaries were black and that is how he identified it.
Now up here, that is a pretty easy way of distinguishing the two common gull species, the Glaucous Gull lacks black on the wings. But that wouldn't work everywhere, and I wanted to extend his gull ID knowledge, so I brought up a photo from Saturday of two Thayer's Gulls that was more detailed. Or at least I thought it was of two Thayer's.
I pointed out to Travis that the iris of the Thayer's Gull is dark, but when I looked at the second gull I saw that the iris was yellow, not dark. It wasn't a Thayer's! But what was it?
In this case, the tips of the primaries were grey, not black. I zoomed in to see the colour of the orbital ring (the small ring around the eye) which was red. The gull was an Iceland Gull. But more specifically (see what I did there?) it was a Kumlien's Iceland Gull, a sub-species of Iceland Gull, Larus glaucoides kumlieni. The other form Larus g. glaucoides, is coloured identically to our Glaucous Gull, the differences between the two are subtle. I've seen glaucoides here in the past, in fact, with the exception of last year, I usually see at least one here each spring. This is the first time I've noticed a Kumlien's Gull here, which isn't to say they haven't been around, I may have missed them. I almost missed this one.
Kumlien's nest on Baffin Island, south of here, roughly on the south half of Baffin, and Larus g. glaucoides nests on Greenland. You would expect that Kumlien's would be the one usually seen. But so far that hasn't been the case.
The walls we put around species to define them are tenuous at best. This is especially evident in the Larus gulls. Although Thayer's Gulls and Iceland Gulls are recognized as separate species by the A.O.U., they are likely two forms of the same species. This article points out the science and history about Thayer's as a recognized species.
At any rate, thanks to a photo I took spur of the moment, while waiting on my belly for a Red-throated Loon to swim closer, I now know that, in at least one case, Kumlien's Iceland Gull comes as far north as Arctic Bay.
The photo: Thayer's Gull on the left, Kumlien's on the right.
Detail: Thayer's
Detail: Kumlien's
Comments
2 responses
Amazing! I’d never have noticed those differences.
They are subtle. That is one of the things that is so cool about gulls and why it drives me to distraction when people lump them all in as “seagulls”. Gulls have some incredible identification challenges, and I pretty much stick to adult/breeding plumages. Throw in all the transition plumages between fledgling and adult, not to mention the hybridization and its crazy.