** Reply to note from Ruth Sullivan

> Hi Eugene,
> I have the feeling lot's of Birders going home with seeing the dark
> Western, instead of the Real Slaty-backed Gull.The reason i say this, most
> of the time i hear the call the dark western the real Gull, to i point out
> this Gull is a Western Gull otherwise there would go home, that there saw
> the Slaty- backed Gull.If you have the new Fall Issue of Field Notes:The
> Cover is a Kelp- Gull, the Slaty-backed looks that dark.We had three
> Western there, but i only have to look at the Bill at the western and i
> know this isn't the real Slaty-backed. the colour of bright yellow alone
> makes it a western.The Slaty have a pale straight Bill, the Western have a
> white Head, the Slaty have smal brownish pin- stripes what NO other Gull
> have there.I can pick this Gull out anytime, because it is the typical
> Species,what a real Slaty- backed Gull should look like, wy make more
> complicated than it is?

I have been staying out of this one but can't any longer. The bird in Ruth's
photos is a Slaty-backed all right, but a *very* dark-mantled one. Just about
the darkest you could expect to find in the species. I stress that there is
a lot of variation in the mantle color of a Slaty-backed Gull, not only between
birds, but within an individual itself depending on light conditions. I believe
that this is because a great deal of a Slaty-backed's mantle color comes from
structural feather refraction rather than pigmentation. I sent Steve Hampton
in California a bunch of SBGU slides which he will scan and put up on his web
page shortly. Steve will let us all know when he has it ready. Then we can all
check out the photos for ourselves and see what I am talking about.

- Jack

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Jack Bowling
Prince George, BC
jbowling at direct.ca