[obol] Re: North Portland CBC Highlights
- From: "Phil Pickering" <philliplc@xxxxxxxxxxx>
- To: <obol@xxxxxxxxxxxxx>
- Date: Sun, 1 Jan 2017 09:30:19 -0800
Finally, we found a rather interesting gull, one that
appears to be a GLAUCOUS GULL HYBRID. Pictures are
in the ebird report below. We welcome any feedback,
as it is a somewhat puzzling bird.
http://ebird.org/ebird/view/checklist/S33320401
That is a confusing bird, but again it’s a 2nd-winter
so the bill pattern isn't necessarily an indication of
Glaucous in its lineage. It is fairly common for both
Herring and Thayer's to have this bill pattern in their
second year. And although Glaucous-winged rarely
develop a bill pattern quite this cleanly delineated
some do fade into a black-tipped pale bill from 2nd-
winter on (good example in Howell 33.20).
This and the gull Jacob posted from Newport can be
aged as 2nd-winter or older based on the smoothish
or mottled rather than finely checkered (juvenile) coverts,
along with the very rounded tips to the outer primaries
which are apparent in these photos. Takes practice to
see but 1st-winter birds do typically have detectably
more of a point to the outer primaries than either of
these birds show.
The Heron Lakes bird looks superficially like a large 2nd-
winter Thayer's but with a funky banded pale tail, so I
would primarily be considering Herring x Glaucous-winged
in this case. Birds that are presumed to be of that mix tend
to mimic Thayer's in appearance.
And to clarify I think the Newport bird is probably
within the normal range of appearance for pure(ish)
Glaucous-winged. Or at least I don't see any obvious
reason to suspect it is a Glaucous hybrid.
Cheers, Phil
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