Maybe, just maybe, another Slaty-backed Gull.
To make matters more interesting, a bird observed yesterday in Half Moon
Bay, San Mateo, could be a first cycle Slaty-backed Gull. The identification
of this age class is very problematic, particularly due to the great
variation in Slaty-backed at this age. However, this bird was structurally
unique (versus Westerns, Glaucous-wings and Herrings) and had features that
suggest Slaty-backed. I would appreciate comments, yes negative ones even,
on the tentative identification, particularly from those seeing Western
Gulls in their home patch.
Don't let the birds of Chile header confuse you... I need to make a new one
for these ID pages!
Half Moon Bay, CA
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