Thayer's or Iceland (Kumlien's)

[John Chardine]

This gull was mixing with other gulls (Herring, Great Black-Backed, Iceland) at a freshwater pond in Truro, Nova Scotia recently. Although Iceland and Thayer's are closely related, hybridise, and have been considered the same species, I would be interested in people's opinion of the ID. I would have called it a Kumlien's based on the grey wing-tips but I don't think the dark eye is right for Iceland.

Sorry about the partial Mallard under the bird!

Canon EOS 50D, 500/4
capture date: Saturday, 17 January, 2009 1:42 PM
exposure program: Aperture Priority
ISO speed: 400
shutter speed: 1/8000
aperture: f4.5
exposure bias: +0.0
metering: Pattern
flash: OFF

[Wayne Richardson]

Hi John

We can safely say (for certain) this is not the nominate race of Iceland. :)

However, I'm a lot more circumspect regarding the very much more inconsistent Kumlien's! The view of the primaries is less than ideal, but the markings appear to be grey (as you say) rather black. Thayer's are pretty constant in that the primary markings are black/blackish & always darker than Kumlien's, although the occasional individual may come close in shade.

The eye colour is very variable in Kumlien's with most darker than nominate & some do have dark iris just like Thayer's. If this characteristic was your only reason not go for the Iceland SSP, then I don’t see it as an ID issue.

Cheers: Wayne

[John Chardine]

Thanks Wayne. Here's another view, this time with the wing-tips showing. I think you are right though- we have a Kumlien's. The back is quite light and the wing-tips are perhaps lighter than a Thayer's would show. This bird shows more dusky around the head and neck than I would expect in a Kumlien's, this is the common one in these parts. As far as I know Thayer's are not seen that often.

[Richard Stern]

Hi,

Even on the top picture, the dark on the upperside of the primaries looks neither dark nor extensive enough to call it a Thayer's, and the legs don't look "bubble gum pink" enough, so I would have let it go as a common or garden (in the Maritimes) Kumlein's. The few Thayer's I have seen look like Herring gulls with dark eyes and bright pink legs, and of course a different pattern on the underside of the primaries. Now, whether Thayer's, Kumlein's and Iceland are 1, 2 or 3 different species, or races (of what?) is a whole 'nother ball-game.

Richard

Richard