Wayne raises some good points and certainly if this bird is heading into its
first fully “adult” summer I would not be surprised at a few dark feathers on
the face. Gulls are a source of endless, er, pleasure.
Alan Contreras
Eugene, Oregon
acontrer56@xxxxxxxxx
On Feb 28, 2016, at 5:12 PM, Wayne Hoffman <whoffman@xxxxxxxx> wrote:
Hi, Beverly –
I disagree with Alan about this bird in some respects. I would not identify
it as a Slaty-backed from these photos, but consider it suggestive. It is
hard to call any bird a Slaty-back without seeing the wingtip patter, pretty
much hidden in these photos. The one photo that does show wingtips somewhat,
above the shoulder of the Herring Gull, shows a lot of white – possibly more
than typical of Western. The same photo seems to show a clear, very pale
iris consistent with Slaty-backed. Alan is correct that winter Slaty-backs
have a more hooded look, but this is the end of February, and many of the
gulls with winter hoods (e.g., Glaucous-winged, California, Mew, and Herring)
have begun to replace the darker feathers with the white of summer plumage,
so a Slaty-back at this date might have less hood than it did a month or two
ago. Some of the details of shape and leg color look a bit more like
Western, as Alan suggests, but I do not see any of them as definitive.
I also disagree with Alan’s suggestion of dubious ancestry. Certainly some
of the Western-like gulls on the Oregon coast have Glaucous-winged Gulls in
their family tree. Those birds (adults) tend to also be intermediate in
mantle color; i.e paler than “pure” Westerns. Westerns vary geographically
in mantle color, paler here at the northern end of their breeding range, and
progressively darker to the south (although quite a few of the darker
southern birds move north when not breeding). This bird and other birds with
darker backs than our residents are unlikely to get their winter head
markings from Glaucous-winged Gull ancestors. Instead, it’s pretty clear
that a minority of adult or near-adult Westerns do develop some dark color on
their heads in winter.
Here is one explanation that I have provided in the past. Sub-adult
Westerns (3-4 year olds) often have heavy winter hoods. They also have some
black in their tails, and often in their bills, some brownish primaries, and
other signs of immaturity. It appears that a few of these bird may continue
to develop some of the winter head pattern after reaching adulthood, when
most Westerns retain pure white heads. I do not like to assume mixed
ancestry for these birds unless one or more other characters also appear
intermediate (iris color, eye-ring color, mantle color, bill color).
Wayne
From: obol-bounce@xxxxxxxxxxxxx <mailto:obol-bounce@xxxxxxxxxxxxx>
[mailto:obol-bounce@xxxxxxxxxxxxx ;<mailto:obol-bounce@xxxxxxxxxxxxx>] On
Behalf Of Alan Contreras
Sent: Sunday, February 28, 2016 11:53 AM
To: mapsout@xxxxxxxxxxx <mailto:mapsout@xxxxxxxxxxx>
Cc: OBOL
Subject: [obol] Re: Nehalem Bay-Dark smokey gull with smudgy eye -
Slaty-backed or Olympic??
I think if this were a Slaty-backed it would have brighter red-pink legs, a
more “hooded” look with lots of speckles, probably a yellower eye and
probably a somewhat smaller bill. So my vote goes to Western with a dubious
grandparent.
Alan Contreras
Eugene, Oregon
acontrer56@xxxxxxxxx <mailto:acontrer56@xxxxxxxxx>
On Feb 28, 2016, at 11:47 AM, Beverly Hallberg <mapsout@xxxxxxxxxxx
<mailto:mapsout@xxxxxxxxxxx>> wrote:
Hi all,
Yet another gull question (sigh)... Maybe you could help id this dark gull
that was just south of the Nehalem Bay SP boat launch this morning with a
roost of gulls. The gull seems larger-bulkier and has less blue tones than
the nearby Western Gull to it's right. The gull has the smudgy eye and it
had some streaks on the back of the head. There is also a Herring Gull in
front of him for comparison.
There are four pics altogether on Flickr.
PS - I still have a Mountain Chickadee visiting my feeder daily in
Manzanita/Nehalem.
PSS - I had a Rufous Hummingbird on the 23rd and a bird-loving neighbor
nearby says she saw a Rufous Hummingbird in her neighbor's yard a couple
weeks before that!!!
https://flic.kr/p/ECopz6 ;<https://flic.kr/p/ECopz6>
https://flic.kr/p/ECorsp ;<https://flic.kr/p/ECorsp>
https://flic.kr/p/DEEkpL ;<https://flic.kr/p/DEEkpL>
https://flic.kr/p/EuahAM ;<https://flic.kr/p/EuahAM>
Thanks, Beverly Hallberg
