Re: Yellow-legged Gull at Crandon


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Posted by Rock Jetty on 23:28:20 03/23/11

In Reply to: Re: Yellow-legged Gull at Crandon posted by Larry Manfredi

Hello all,

I agree with Michael Brothers and Cameron Cox with regards to this bird potentially not being a Yellow-legged Gull and instead a good candidate for a Herring X Lesser Black-backed hybrid. However, I am not convinced that this is just a Lesser Black-backed Gull.

I'd like to point out a few key features on the Crandon bird, some already commented either in this bird board or in BIRDBRAINS. These features are described in Olsen and Larsson, 2004.:

Larry's photo shows a broad black band on the P5 - this is the fifth primary (remember, you start from the tip with P10 and work your way up). Now, this is a good characteristic for Yellow-legged Gull, however, the outer web of the band (toward P10) seems broader than the inner web - a possible indication of hybridization between Herring Gull (argentatus) and Lesser Black-backed Gull (fulcus).

Head seems rounded, less squared.

Orbital ring appears orange instead of red.

Feet appear fleshy-colored.

The graellsii race of the Lesser Black-backed gull has a slate-colored mantle and thus comes close in resemblance. However, it is my belief that the orbital ring should then be red and the legs should lack the fleshy coloration in the feet. The Crandon bird is an adult bird, I don't think there is any transition going on.

That said, I hope I'm wrong and it is a Yellow-legged Gull.

-RJ



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