Date: 7/10/17 1:46 pm
From: Wayne Hoffman <whoffman...>
Subject: [obol] Taxonomic Changes (long)
Hi - 

Thanks to Tom Crabtree, Bob Obrien, and others who have commented on the recent AOU (oops AOS) changes and posted links.

I have gone through the committee members' posted comments, and have developed some summaries and my own commentary for the species most relevant to Oregon birding.


1.        1.  Change genus of Latin names of Snow, Ross’s and Emperor geese from Chen to Anser [10 yes votes, 1 no].   One member commented,  “…maintaining  Chen renders Anser polyphyletic.”  This is a common reason for changing genus names.  What it means is some species in Anser are more closely related to those in Chen than to at least one of the others in Anser  (Bar-headed Goose).   The intent is that all of the species in a single genus should be monophyletic, meaning that they are all more closely related to each other than to any other species not included in that genus.
2.     2. Split Red Crossbills: YES!!! [8 yes, 2 no].   We have known for over 20 years that “Red Crossbill” is a complex of multiple species, so it is great to see its dismemberment commence. This is a special case involving an endemic to southern Idaho, less than 200 miles from Oregon, but hopefully the others will be resolved soon.  More about crossbills in another post.
3.       3. Change the Latin name of the Northern Harrier to Circus hudsonius [all yes].  AOS now agrees with European ornithologists that American Northern Harrier is not the same species as Eurasian Hen Harrier.
4.       4 Split Yellow-rumped Warbler into 3 species [Failed: 4 votes to split, 5 against].  Recent research reports indicate that “Myrtle” and “Audubon’s” warble interbreed in NW Canada, and in at least part of that area, they seem to choose mates pretty randomly, HOWEVER there seems to be selection against the hybrids.  So this is pretty much on the line in terms of species status, and I expect this split will not happen unless the makeup of the committee changes to include more people inclined to be “splitters.” I am not sure what other research results could be, that would change the current committee’s decision.
5.       5. Split Willet into 2 species. [failed, 6 yes, 4 no].  Two populations with overlapping ranges in winter and migration but separate breeding ranges.  Some plumage and size differences, but not major.  Some experimental evidence that Atlantic ones do not respond to calls of western ones.  This split might happen in the future if the committee gets more splitters, or if more work on vocalizations amplifies these results.
6.       6. Change species limits in Juncos.  They split the ones from southern Baja as a separate species, but did not change status in North America.  General sense of the comments is that the current taxonomy north of Mexico might need changing, but they want more data before doing it.
7.       7. Lump Common Redpoll and Hoary Redpoll [failed 5 yes, 5 no].   They want more evidence from breeding areas.  The cited evidence is all over the map:  some studies show assortative mating, some do not.  Recent widely publicized study of wintering birds in the northeast did not seem to impress them much.
8.       8.  Change Latin name of Northern Shrike to Lanius borealis.  This is the result of splitting it from the Great Gray Shrike of Europe and western Asia, which retains the name Lanius excubitor.  This split is not surprising but the name excubitor was so cool – I’ll miss it.
9.       9. Change Genus names of several dabbling ducks. Genetic studies show that Anas is paraphyletic, i.e. some Anas species are more closely related to some tropical species that are not currently included in Anas than to others  that have been in Anas. Two possible ways to fix this would be to add those tropical species to Anas to make one very large monophyletic genus, or to split Anas into multiple monophyletic genera (what they did).  This resurrects genus names that you might find in pre-1957 guides and references.  Note that this “fix” is opposite to the one for geese.  This is because they judged the differences between groups within Anas to be deeper (result of longer evolutionary divergence) than the differences between groups in Anser.
10.   10. Split Nashville Warbler [failed, 6 yes 4 no].  Two of the No voters seemed to waver, and suggested more info needed, so this may happen in the near future.
11.   11. Lump Thayer’s Gull into Iceland Gull.  [unanimous Yes ].  I was disappointed by this.  Essentially, they discounted a publication by the late Neal G. Smith that has been challenged as potentially fraudulent, then made the decision based on other information.  I agree with tossing the Smith publication, but consider the info that they did use to be sketchy and incomplete.  This info was mainly three studies, all before 2000, that found mixed colonies with apparent interbreeding of Thayer’s and (Kumlein’s) Iceland Gulls.  Oddly, one piece of information that does not support lumping was not mentioned in the petition to lump, nor in the committee members comments, even though it was summarized in a publication co-authored by one of the authors of the petition (Jon Dunn).   This is an analysis, summarized on p. 252 of Steve Howell and Jon Dunn’s book Gulls of the Americas, that shows variation in wingtips of a large number of Iceland  Gulls, but indicates they could not find many Iceland X Thayers hybrids.  So it appears adult hybrids are rare in the area where Kumlein’s Icelands winter, and our experience here is that hybrids are very rare on the West Coast where Thayer’s winter.  So if these taxa are widely interbreeding, where do the hybrids go?  Thus, this situation resembles that of Yellow-rumped Warblers:  some, (but in this case not very extensive) evidence that they do not mate assortatively, but also not much evidence for hybrids being common.  So maybe, like the warblers, hybrids do not survive very well? IMO the bottom line is that a lot more research needs to be done in the arctic and the potential wintering areas.
12.   12.  Split Bell’s Vireo into a Western and an Eastern species [Failed 5 yes, 5 no].  Bell’s Vireos are rare strays to Oregon with only 2 records in the OBRC archives, both from Fields.  The issue for Oregon is that these and future occurrences might be hard to identify to species, and both are somewhat plausible strays to Oregon.  This proposal failed because the two forms come closest to each other in New Mexico, and state officials denied permission to collect samples for genetic analyses (including denying permission to take samples of single feathers, or of blood, both of which are routinely done elsewhere without seriously hurting the birds).  The committee expressed hope that in the future, the state would allow sampling.



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