Date: 3/30/17 11:02 am
From: Wayne Hoffman <whoffman...>
Subject: [obol] Re: BREAKING NEWS
There may be more genetic evidence, but oddly this proposal to lump does not detail that stuff, instead as Lars pointed out, it is more focused on punishing Smith. [Punishment usually works better when the subject is still alive.]

There is a major issue with the interpretation of the genetic data, however.  Currently the dominant model of avian speciation involves gradual divergence in allopatry as a response to differeences in local environments, and gradual accumulation of genetic differences in supposedly neutral parts of the genome.  The amount of difference accumulated then becomes an estimator of how long the populations have been evolving separately, and hence whether they have accumulated as much difference as "sister species" typically have.  This model seems to work well for the majority of bird groups,  However, in several groups, "special circumstances" are allowing populations to evolve much faster, so that the "neutral" regions of the genome do not reflect the amount of divergence that has actually happened. These groups include crossbills and perhaps some other finches, northern hemisphere geese, prairie grouse, possibly juncos, and large white-headed gulls.

To reiterate, for these groups the rules about divergence time that work pretty well for other bird groups, give bad results.

In 1999 Dick Banks and Ralph Browning (who I think now lives in Jackson County) wrote a short paper about Thayer's gull taxonomy hat asked 6 questions they felt needed to be answered before Thayer's Gull taxonomy should be changed.  Basically they wanteda bunch more science.  It is disappointing how few of those questions are addressed in the current proposal.  It is also telling that the only source younger than 1999 cited in the proposal is the 2002 BNA account (written by Snell).

Wayne
On 3/30/2017 8:13:42 AM, Mike Patterson <celata...> wrote:
Mr Norgren seems quite passionate on this subject...

I have read just about every actual paper on this including
the infamous exchange of buttals and rebuttals between Snell and Smith.
I do not believe that Smith faked data, but I think he relied more
heavily on the aid of locally sourced assistants than he admitted to
and I think that those who eventually peer-reviewed his work were
so enamored by the experimental design and outcomes in line with their
expectations regarding Mayrian Evolutionary Theory that they failed
in their duty to be objective and conservative (and I mean conservative
in the dictionary sense, not the oxymoronic political sense).

There is, however, more to this proposal than the he-said, he-said
tiff between Snell and Smith, including an increasingly damning body
of genetic evidence... and I've read much of that stuff as well.

Lumping Thayer's Gull will bring the AOU into line with almost every
other Ornithological Group in the world, most of those groups have been
in a splitting mood regarding many other gull species.

Now, having said all that, I can find reasons to favor any of the
competing Iceland/Thayer's scenarios and I encourage Mr Norgren to
submit his own proposal to NACC. I believe the only requirement is
membership in the AOU. The Iceland/hybrid-swarm/Thayer's hypothesis
has many champions.

And for the half-dozen or so folks on OBOL who find arguing about gulls
enlightening, I recommend they start their journey down the
Iceland/Thayer's rabbit hole at:

http://www.ofo.ca/site/page/view/articles.thayer

This page is well sourced and will provide a starting point for
collecting and examining the actual source material. It does
not include many of the more recent genetic studies which show
very little separation between Iceland/Kumlien's and Thayer's
nor any consistent geographical patterns of distribution.

A good started paper for that (and one you can get for free) can be
found at:
https://www.researchgate.net/publication/7692222_Phylogenetic_relationships_within_the_Laridae_Charadriiformes_Aves_inferred_from_mitochondrial_markers



Lars Per Norgren wrote:
> I view this proposal as bunkum. Dun and colleague bring no new or
> substantive evidence to the century old debate.

--
Mike Patterson
Astoria, OR
That question...
http://www.surfbirds.com/community-blogs/northcoastdiaries/?p=3294
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