[Tweeters] re: Moses Lake Lesser Black-backed Gull

Wayne C. Weber contopus at telus.net
Fri Apr 6 09:50:14 PDT 2007


If anyone is "missing the point" here, I believe it's you. The point is,
that normal patterns of geographic occurrence are an
important factor to take into account in determining an identification.
Lesser Black-backed Gulls have a well-established pattern of
occurrence in inland western North America. (I personally have
seen individuals all the way from inland southern British Columbia
to northern Mexico.) Heuglin's Gulls have no such known pattern.
Therefore, if there were a bird which could answer the description
of either, it is overwhelmingly more likely to be a Lesser
Black-Back. It's a simple exercise in logic.  The burden of proof
should be on the person who is trying to prove that it's the more
unlikely species (in this case, Heuglin's Gull).

Using the same kind of logic, if I see a meadowlark in
Washington, I can be at least 99.99% certain that it's
a Western Meadowlark, not an Eastern. Or, to pick another
species that's a vagrant in this area, if I see a Tropical/Couch's
Kingbird in western Washington, I can be virtually certain that
it's a Tropical. Evening though the two are quite hard to
distinguish, there is a regular pattern of occurrence of
Tropical Kingbird in Washington, and no such pattern for

In the case of the Moses Lake gull, there is NOTHING about it that
is inconsistent with a Lesser Black-backed, so I am quite
satisfied to call it that.

Also, you may consider yourself a larophile, but please do not
include me in that group. Although I read most or many of the messages
on ID-FRONTIERS about gull identification, I tire quickly of the
endless debates about the identity of some individuals which are
not identifiable with certainty from the evidence at hand. I am
quite happy to admit that some individual birds cannot be safely
identified, and I get impatient with those who insist that there must
be SOME way to identify "Gull X" beyond question, and who indulge
in endless speculation about such birds. I hope you are not one of
the latter.

Happy gull-watching!

Wayne C. Weber
Delta, BC
contopus at telus.net

----- Original Message ----- 
From: "Nigel Ball" <nigelj.ball at gmail.com>
To: "Wayne C. Weber" <contopus at telus.net>
Cc: "Doug Schonewald" <dschone8 at donobi.net>; "TWEETERS"
<tweeters at u.washington.edu>
Sent: Thursday, April 05, 2007 11:00 AM
Subject: Re: [Tweeters] re: Moses Lake Lesser Black-backed Gull

With respect, Wayne, you might be missing the point a bit. No
larophile worth their salt wants to turn something into something
else. But it would be absurd to accept all dark backed yellow legged
gulls as lessers just because all the previous ones have been so
This thread has been about critical review and consensus. In
undertaking the work (for which Ryan and Doug and others are to be
commended) we will end up surer of the ID and wiser about molt cycles,
aging, bill marks, gape color, leg length... And without such review
the first heuglini at the SaltonSea or half-moon bay would cast doubt
on all LBBG records in WA...

Actually, my real reason for writing is that I find the speculation a
blast. Keep it up boys!

Nigel Ball
bainbrige island
nigelj.ball at gmail.com

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