Comments on: More February Mystery Gulls http://www.sitkanature.org/wordpress/2007/12/19/more-february-mystery-gulls/ An Aspiring Naturalist Learns His Place Tue, 16 Mar 2010 06:04:48 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Gentoo http://www.sitkanature.org/wordpress/2007/12/19/more-february-mystery-gulls/comment-page-1/#comment-31731 Gentoo Sat, 19 Apr 2008 20:44:54 +0000 http://www.sitkanature.org/wordpress/2007/12/19/more-february-mystery-gulls/#comment-31731 I think this is a Glaucous-Winged Gull. A lot of GWGU's often have head and bill shapes similar to Thayer's Gull. Some are even like Herring Gull in proportions. Sibley also notes this. A Thayer's would show more black primaries on the closed wing when folded and view from the upper surface. That is if you're looking at the wing closest to you. The far wing would not show any black on the underside of the primaries. When the wings are open, the pattern in the wing of Thayer's is still quick black but the black is restricted to the outer webs of the primaries and often there are large long tongues which end in a large pronounce whitish moon. This last characteristic is quite variable though. Some Glaucous-Winged Gulls can also have pale eyes, a few even paler than your bird. This bird above appears to have just very slightly darker the the mantel primaries which could indicate some hybrid gene flow in it's past, perhaps with Herring Gull. I think this is a Glaucous-Winged Gull. A lot of GWGU’s often have head and bill shapes similar to Thayer’s Gull. Some are even like Herring Gull in proportions. Sibley also notes this.

A Thayer’s would show more black primaries on the closed wing when folded and view from the upper surface. That is if you’re looking at the wing closest to you. The far wing would not show any black on the underside of the primaries. When the wings are open, the pattern in the wing of Thayer’s is still quick black but the black is restricted to the outer webs of the primaries and often there are large long tongues which end in a large pronounce whitish moon. This last characteristic is quite variable though. Some Glaucous-Winged Gulls can also have pale eyes, a few even paler than your bird.

This bird above appears to have just very slightly darker the the mantel primaries which could indicate some hybrid gene flow in it’s past, perhaps with Herring Gull.

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