Re: Back River WWTP 4/10

Rick Blom (rblom@blazie.com)
Sat, 11 Apr 1998 08:32:55 -0400


A follow-up to Gail and Barry's report from Back River. I can add a Common
Yellowthroat to the mix, seen after we split up. Also, my total of Laughing
Gulls was 18.

I should add a comment about the smaller one we saw. About a dozen years
ago I measured the Laughing Gull specimens at the Smithsonian while working
on comments on the identification of a Laughing/Franklin's Gull in Britain.
Much of the controversy hinged on the small size of the bird. I found that
the Laughing Gull breedings in the southern U.S and in the Caribbean were,
on average, smaller than the birds breeding on the Atlantic Coast. In some
instances the differences were striking, but they were clinal and there are
no subspecies recognized. The point of the exercise was that a Laughing
Gull in Britain (it was a Laugher) could have as easily come from the
Caribbean (following Gulf Stream) as from the northeastern U.S. As a
consequence I noticed that when I was in Brownsville in the spring that the
size difference was not a great between Franklin's and Laughing as it is
when I see Franklin's here.
        The bird we saw yesterday was notably small, but there is great
individual variation in gulls and it is just as likely that this was a
small bird as it is that the bird is from one of the southern colonies. It
was just a bit of an eye-grabber on a day when there were (inexplicably) no
Little Gulls or Black-headed Gulls we could find.

Rick

"Lack of education is an extraordinary handicap when one is being
offensive."  Josephine Tey

Rick Blom
rblom@blazie.com
Bel Air, Maryland