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Thayer's Gull, Westmoreland Park, Portland
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Portland, OR, October 2011
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This hatch-year Thayer's Gull was at Stewart Pond in Roseburg, OR 9 December 2011. After noticing the conspicuous black smudge through the eye on this bird, I saw several other same-aged birds at the Rogue River mouth that had the same marking.
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Thayer's Gull preening, Portland, OR
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Thayer's Gull (adult), Feb 11, 2012, Lewes, DE Pelagic
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Thayer's Gull (adult), Feb 11, 2012, Lewes, DE Pelagic
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Portland, OR, Feb. 2011, first cycle
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Portland, OR, Dec. 2010, adult with pale iris.
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This adult (fourth cycle plus) Thayer's Gull was at the 'gull puddle' along the south jetty of Yaquina Bay on 10 January 2014. Note that the iris is pale, but not nearly as pale as the Herring Gull's (previous images). Also notice how many of the feathers immediately surrounding they are dark, which creates a smudgy look around the eye. The bills of winter adult Thayer's often look a bit washed out. If you look closely at the folded wingtips, you can see that the exposed underside of the right primaries is paler and not black. This bird clearly looks short-legged, something that I often notice on Thayer's Gulls.
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Of all the gulls that Shawneen Finnegan and I studied at Clackamette Park, Clackamas County, OR on 2 February 2014, this was one of the most interesting individuals. At first glance, its dark coloration and pattern are suggestive of a first-cycle Western Gull, but it was no larger than a Thayer's Gull by direct comparison and it had a rounded head and fairly small all-dark bill. The spangled pattern on the tips and distal margins of the tertials is consistent with young Thayer's based on the photos of first-cycle Thayer's in Howell and Dunn. We were also a bit surprised by dark brownish look to the legs.
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Here's another shot of the same small dark first-cycle gull at Clackamette Park, Clackamas County, OR on 2 February 2014. I suspect that it is a Thayer's based on comparisons with dark first-winter Thayer's in Howell and Dunn.
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Here's another light angle of the same gull as the one in the previous image, at Clackamette Park, Clackamas County, OR on 2 February 2014. Note the crisply spangled coverts and tertials.
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This bird, at Clackamette Park, Clackamas County, OR on 2 February 2014, begs the question, where does Kumlien's Gull end and Thayer's begin. The extensive spangling on the edges of the tertials is consistently shown by gulls labeled as first-cycle Kumlien's in Howell and Dunn, whereas their first-cycle Thayer's show darker overall tertials, with spangling mostly limited to the distal end of those feathers. The next several images are of the same bird.
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This apparent adult Thayer's Gull, at Clackamette Park, Clackamas County, OR on 2 February 2014, had a particularly light eye. If you look closely, you can see the pale underside of the right wing tip.
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Here's another shot of the light-eyed adult Thayer's Gull at Clackamette Park, Clackamas County, OR on 2 February 2014. Again, you can see the pale underside of the right wing tip.
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In this shot of the same gull, at Clackamette Park, Clackamas County, OR on 2 February 2014, not the small, short bill, small rounded head, shortish legs and heavily spangled tertials. The centers of the primaries seem too dark for Kumlien's.
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Here's a dorsal view of the same puzzling Thayers/Kumlien's Gull at Clackamette Park, Clackamas County, OR on 2 February 2014.
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Yet another angle of the puzzling Thayer's/Kumlien's type gull at Clackamette Park, Clackamas County, OR on 2 February 2014.
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Thayer's Gull is the second largest of this group of five superficially similar species and perhaps the species that is most confounding for birders. The black on the wing tip is fairly restricted and this species has an underwing that is least like the upper wing, showing almost no jet black below. In the Pacific Northwest, hybrid Western Gull X Glaucous-winged Gulls ("Olympic Gull") often show a similar difference between the upper and under wingtips. This similarity results in lots of mis-identifications and a general lack of confidence about identifying this species. As seen in this image, Thayer's tend to have darker more crisp mottling on the head and neck, plus their bills are shorter and thinner and their overall size is smaller than the large, bulky and heavy-billed Olympic Gulls.
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This dorsal shot of flying Thayer's Gull does a much better job of illustrating the strong difference between the amount of black on the upper surface and undersides of the outermost primaries. In many lighting situations, the underside of a Thayer's Gulls wingtips often looks mostly silvery and gray to dusky-gray (very little black) with just a narrow trim of black (formed by the subterminal black spots) right at the wingtip.
Photo Info