Tweets,



Long.



If you have heard enough about gull controversies, hit your delete button
now.



Thanks to Hal Opperman's technical references in support of the latest
revisions in gull taxonomy, most notably an article by J.-M. Pons, A.
Hassinin, and P.-A. Crochet published in Molecular Phylogenetics and
Evolution in 2005 where they analyzed mitochondrial DNA sequences (those
transmitted straight down the female lines without recombination with
paternal DNA) of some 50 species of the world's gulls, all or nearly all,
depending on your preferences for splitting or lumping.



I had complained that the move on our most recent checklist of the Western
Gull to sit between Ring-billed and California and at some remove from
Glaucous-winged seemed odd given the apparent similarities and extensive
hybridization of these two species. It seemed as if the lab guys with their
probabilistic DNA analyses were running the show, ignoring the "common
sense" of field observations.



It seems this is a considerable exaggeration. In fact, the DNA evidence Pons
et al. consider fit field observations quite nicely in the great majority of
cases, with exceptions due either to convergent evolution -- e.g., the
Heermann's Gull resembling the Grey and Lava Gulls of South America in dark
body coloration, likely an adaptation to tropical conditions rather than
evidence of common ancestry - or to the distortions imposed by representing
a multi-dimensional pattern of relationships in a single, often arbitrary,
linear sequence, as in a checklist - as with the a core set of "typical"
gulls.



Let's compare the "old" with the "new" Washington State gull lists:



Old: Laughing, Franklin's, Little, Black-headed, Bonaparte's, Heermann's,
Mew, Ring-billed, California, Herring, Thayer's, Iceland, Lesser
Black-backed, Slaty-backed, Western, Glaucous-winged, Glaucous, Sabine's,
Black-legged Kittiwake, Red-legged Kittiwake, Ross's.. Then the terns.



New: Black-legged Kittiwake, Red-legged Kittiwake, Ivory Gull [new],
Sabine's Gull, Bonaparte's, Black-headed, Little, Ross's, Laughing,
Franklin's, Black-tailed [new], Heermann's, Mew, Ring-billed, Western,
California, Herring, Thayer's, Iceland, Lesser Black-backed, Slaty-backed,
Glaucous-winged, Glaucous, Great Black-backed [new].. Then the terns.



Firstly, all the gulls [in the world, in fact] are still gulls and
apparently evolved as a group distinct from the terns, splitting off perhaps
13 million years ago (or maybe twice that. they're still debating that
issue), then beginning to diverge to become the variety of gulls we know
today some 3 million years ago (or maybe 11). So far, so good.



A major division between "tern-like gulls" ("Sternines") and more typical
gulls ("Larines") has been proposed but is as yet not proved. In any case,
our current list begins with the "tern-like gulls," first the two kittiwake
species (genus Rissa), then a new grouping putting Ivory and Sabine's Gulls
together (though Pons et al. prefer to keep them in their old genera,
Pagophila and Xema respectively). So far all we've done is move these four
species from the end of the old list to begin the new, next to Laughing and
Franklin's. Another realignment amongst the "tern-like" gulls is to join
Little and Ross's Gulls in a new genus, Hydrocolaeus (in place of
Rhodostethia for the Ross's and removing the Little Gull from the typical
gull genus Larus). Bonaparte's and Black-headed are shown to be closely
related, as we have assumed all along, but are removed from Larus and
placed in a new genus Chroicocephalus and included with the other
"tern-like" gulls.



Laughing and Franklin's, however, fall out genetically with the typical
gulls, despite their black hoods, so must be moved next to the core typical
gull grouping. The Asiatic Black-tailed Gull Charlie Wright discovered at
North Cove is also included with the "Larine gulls" but in a class by itself
(though related to certain southern hemisphere species).



We are left with the following "typical gulls" (as in the old list):
Heermann's, Mew, Ring-billed, California, Herring, Thayer's, Iceland, Lesser
Black-backed, Slaty-backed, Western, Glaucous-winged, and Glaucous. In the
new list there is but a single change. Western shifts to between Ring-billed
and California [plus Great Black-backed is added at the end].



The DNA evidence suggests that Heermann's splits first, then Mew [based on a
European Common Gull sample only], then Ring-billed, then Western along with
the Yellow-footed Gull of the Gulf of California (not as yet on our state
list). The rest: California, Herring, Thayer's, Iceland, Lesser
Black-backed, Slaty-backed, Glaucous-winged, and Glaucous constitute the
Larus argentatus group, named for the European Herring Gull. The authors
note that this group is . "a highly supported clade. of species that are
genetically very similar" and that ". the relationships within this complex
are mostly unresolved" (pg. 693).



One way this might make evolutionary sense is if Western and Yellow-footed
Gulls evolved in a more tropical clime, while the Herring Gull group - at
least those on our state list -- evolved in the North Pacific, but not so
long ago as to prevent Western and Glaucous-winged Gulls from interbreeding
freely when their ranges met.



The fact that Western is placed between Ring-billed and California does not
necessarily imply that these two species are the Western's closest
relatives. As Hal noted, the Tufted Puffin is next to the Rock Pigeon on our
list, but that doesn't mean they are nearest relations. The Ring-billed Gull
should be considered equally distant from all of the typical gulls that
follow in the list. The California Gull is not necessarily any more closely
related to the Western than to any of the other species that follow. The
sequence -- California, Herring, Thayer's, Iceland, Lesser Black-backed,
Slaty-backed, Glaucous-winged, Glaucous -- might as well have been arranged
alphabetically. In fact, in Pons et al. they group them rather differently:
Lesser Black-backed, Glaucous-winged, California, Herring, Glaucous,
Thayer's, Iceland, Slaty-backed. As they note, ". the relationships within
this complex are mostly unresolved."



So, the genetic revolution in bird taxonomy is not so radical as it might
have seemed.



If this isn't enough on this thread, I trust Hal, Dennis, and the rest of
tweeters will add their two-bits.



Dennis is reviewing the yellowlegs situation and will have more to say on
that.



Gene Hunn

18476 47th Pl NE

Lake Forest Park, WA

enhunn323 at comcast.net