Hal, Matt, et al.,



Thanks for the references. I will read them when I get the chance.
Nevertheless, I still find it less than convincing. Recall that Baltimore
and Bullock's Orioles were originally lumped on the strength of what was
then considered convincing genetic evidence of close relationship,
interbreeding freely (at certain locations only, it turned out). Later the
experts changed their collective mind and decided they had been too hasty in
light of more adequate data and analysis. The same happened with the
American vultures being shifted first from their traditional spot amongst
the Falconiformes (a grouping that no longer exists, I take it) to join the
storks, a change long advocated on anatomical and fossil evidence, only now
to be relocated back to where they had been a decade ago (despite the
anatomical and fossil evidence). What's to say the experts won't perform a
more adequate analysis tomorrow of yellowlegs and gulls that shows the
mitochondrial data to have been incomplete or misinterpreted.



As an anthropologist I see parallels with the application of radioactive
carbon proportions in organic samples to estimate the absolute age of
fossil and other remains to date human occupations. A great technical
innovation that has revolutionized our understanding of human pre-history.
However, far from being unambiguous we now know that radioactive carbon
uptake has varied over time and that samples are easily contaminated, both
factors that can seriously bias results. When the elder Dr. Leakey affirmed
the existence of modern human fossils in southern California dated at some
200,000 years ago archaeologists didn't immediately fall in line to accept
this astounding conclusion, not because they were resistant to new evidence
but because this "new evidence" so obviously contradicted a mass of old
evidence and could not be explained by any reasonable evolutionary story.



It seems to me that mitochondrial (and other genetic) evidence should be
used with more caution and treated not as the silver bullet of
biosystematics but as just one piece of evidence that must be shown to fit
with everything else we know about an organism. In the case of the
yellowlegs and the Western Gull it seems the genetic evidence contradicts
just about everything else we know about these birds, morphology, behavior,
biogeography, etc., which ought to raise some doubts. What if tomorrow we
are told that some lab studies have proved that Townsend's Warblers really
belong between Yellow and Nashville, that their close resemblance and
obvious genetic affinities to Hermit and Black-throated Gray Warblers is an
illusion. Or, to exaggerate slightly, if the Black-footed Albatross were to
be stuck between Sooty and Short-tailed Shearwaters having somehow evolved
in a way contrary to everything we thought we knew about evolutionary
change. Or if we are told that Homo sapiens is really a flatworm, despite
superficial resemblances to great apes. Personally, I would take such
assertions with a large grain of salt.



Gene Hunn

18476 47th Pl NE

Lake Forest Park, WA

enhunn323 at comcast.net



From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of Hal
Opperman
Sent: Saturday, February 21, 2009 12:17 PM
To: tweeters at u.washington.edu
Subject: Re: [Tweeters] Gene's query about gulls



Gene and all:



The "weird DNA thing" that led to the AOU's resequencing of the gulls is
laid out in J.-M. Pons, A. Hassanin, and P.-A. Crochet. 2005. Phylogenetic
relationships within the Laridae (Charadriiformes: Aves) inferred from
mitochondrial markers. Molecular Phylogenetics and Evolution 37:686-699. The
revised sequence, and brief commentary, are in the 49th Supplement to the
AOU Check-List in the July 2008 issue of Auk, p. 761sqq.



Hey, not too long ago consensus was that Baltimore Oriole and Bullock's
Oriole were really one species ("Northern Oriole") because they interbreed
so freely where their ranges meet. And then genetic research showed that
they are not even one another's closest relatives, just as it now has for
the Western and Glaucous-winged gulls. The nice thing about science is that
it constantly revises its "certainties."



The AOU's resequencing of the "shanks" (Tringines) that resulted in the
Greater and Lesser Yellowlegs being separated from one another occurred in
the 47th Supplement, in the July 2006 issue of Auk. Again, it results from
genetic research published in a paper they cite.



Hal Opperman

Medina, Washington

hal at catharus.net







On Feb 20, 2009, at 11:05 PM, Eugene and Nancy Hunn wrote:





On another issue, I've been meaning to post a question about the recent
rearrangements of the sequence of shorebirds and gulls in the latest
Washington State checklist. At first I thought it was an editorial oversight
but apparently not:



1) The Willet is now sandwiched between Greater and Lesser Yellowlegs,
and

2) The Western Gull is torn from his familiar moorings beside the
Glaucous-winged and stuck between Ring-billed and California.



I've tried to imagine an evolutionary scenario that would make sense of this
but find it a stretch. Does anyone know the rationale behind these moves? No
doubt some weird DNA thing, but how could Western Gulls not be closest kin
to Glaucous-winged, given that they so freely hybridize?