Stuart,

Thanks for you observations. Would the fact that the Idaho bird is 1st
winter and the Renton bird 2nd winter account for the contrast you note?

Gene.

----- Original Message -----
From: "Stuart MacKay" <stuart at blarg.net>
To: <tweeters at u.washington.edu>
Sent: Tuesday, January 20, 2004 11:56 AM
Subject: Re: Great Black-backed


> Although I cannot profess to be an expert on gulls. I have seen tens of
> thousands of Great Black-backed Gulls and banded a couple of thousand
> birds. My first impression of the photos are that the size and shape
> fits a great black-backed gull - the variation on the species in
> northern Scotland can be quite marked with a few (but not many) as
> small as a herring gull.
>
> My main concern is that the mantle and wing converts seem to be too
> brown. Most of the birds I have seen show greater contrast between the
> light and dark markings on the feathers making the bird appear cleaner
> in appearance. The colouration in Scottish birds can sometimes be
> almost black and white. However the brown colouration could be an
> artefact of the photos - some shots do give the bird a cleaner
> appearance.
>
> I would say that the idaho bird
>
> http://octoberweb.com/birds/gbbg/
>
> is a classic example. While the Renton bird is similar I would expect
> it to show the same plumage markings. Superficially it does but it
> does not seem quite right. I would be less worried about size however
> if the relative size in this photo
>
> http://osprey.bardill.net/gallery/album10/P1170086a
>
> is correct then I would have to say that the bird is a bit on the small
> side.
>
> As for hybridization I am not sure the status of the birds from the
> northeast of North America but in Scotland hybrids are in my experience
> very rare and I cannot recall seeing any while I birded over there.
> Although I realize that the Larus family is considered a complex rather
> than a series of species I think that the experience with Pacific
> Northwest gulls is leading some people to jump to conclusions on how
> 'pure-bred' this bird might be.
>
> I am not sure what the alternative species might be but I don't think
> they can be ruled out.
>
> my $0.02,
>
> Stuart
> --
> Stuart MacKay, Seattle, WA, USA
>