2017 AOS Classification Committee Proposals, Part 1

2017 is a new year, and time for new bird taxonomy proposals submitted to what was formerly called the North American Check-list Committee, of which those approved are incorporated into the ABA Checklist.  Between last year and this year a major lump occurred among bird research institutions, with the American Ornithologist’s Union merging with the Cooper Ornithological Society to form the American Ornithological Society, now the administering body of this list and the committees, which is now called the North & Middle America Classification Committee.

We suggest the usual caveat, that it’s important to note that these are just proposals and the committee has yet to vote on them formally. There are some that are unlikely to make the cut for whatever reason, but in my opinion the proposals are often more interesting than the actual results anyway as we get a peek into the wild world of bird taxonomy as it exists from year to year.

This post will only mention those changes that affect the ABA Area and Hawaii, but if you’re interested in the whole ball of wax – the AOS NAMACC’s (that’s not what they’re calling it, is it?) jurisdiction includes all of the North America south to Panama – please refer to the official list of proposals at the AOS’s website (.pdf).

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Revise the generic classification of the subfamily Anserinae

We’ve come to expect a certain number of taxonomic rearrangement proposals every year, and this one is fairly straight-forward. Currently, North American geese are sorted into three groups – gray geese in Anser, white geese in Chen, and brant-type geese in Branta. New research suggests that the brant-type geese are fairly distinct in the group, but that white and gray geese are not all that dissimilar, and Chen geese should be incorporated into the genus Anser, which is the recommendation here.

Split North American Red Crossbill Loxia curvirostra into two species

Here’s another attempt to unravel the Gordian Knot that is Red Crossbill taxonomy, focusing again on the localized subspecies L. c. sinesciurius, or South Hills Crossbill. A similar proposal was sent to the NACC in 2009, but not accepted, and this one seeks to address the areas where committee members found fault. The most critical new bit of evidence comes from the genetic evaluation of 219 Red Crossbills from across the species’ range, revealing that the South Hills Crossbill is the most distinct lineage among the 9 call types, marking it is the strongest case for a split among Red Crossbills. The new species would potentially called South Hills Crossbill, despite being found in both the South Hills and the Albion Mountains. Alternatively, Cassia Crossbill is a good fit, as both mountain ranges lie entirely within Cassia County, Idaho.

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Transfer Wilson’s Phalarope Phalaropus tricolor to a monotypic genus, Steganopus, Vieillot 1818

All three North American phalaropes are currently treated in a single genus, Phalaropus. This has not always been the case – as recently as 1957, three genera were used for the three species. Of the three, Wilson’s is certainly the odd-bird out, both in phenotype and genotype, and is probably the best case for its own genus as it seems, in many ways, to occupy a sort of midpoint between Phalaropus and Tringa. That said, the question is whether a monotypic genus is appropriate here is one the committee is unlikely to agree with if the comments are any indication. There seems to be at least an equally good case for maintaining the status quo.

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Change the English name of the Ring-necked Duck Aythya collaris

Ring-necked Duck is often near the top of lists of worst bird common names (though as long as the not-olive and not-a-warbler Olive Warbler remains, it will never take top spot), as the eponymous ring is almost never seen. The proposal argues that, at a time when interest in birding is increasing, a common bird with an opaque name is unnecessarily confusing and that birders should take a page from hunters, who have longed called this species “Ringbill”, and adopt the name “Ring-billed Duck”. It’s a fair point, but then we who lead groups of novice birders would be robbed of our most amusing duck anecdote! In any case, it raises the question of the changing nature of what a common name is supposed to be, which is an interesting academic exercise if not a taxonomic one.

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Transfer (a) Intermediate Egret Mesophoyx intermedia and (b) Cattle Egret Bubulcus ibis to Ardea

This is another proposal that calls into question the value of monotypic genera. Intermediate Egret is known from at least one record in the ABA Area, a salvaged individual in western Alaska. Cattle Egret is a common species across the southern third of the ABA Area and increasingly elsewhere. A number of phylogenetic trees embed these two species within the Ardea, so this is a fairly intuitive move. Intermediate Egret is the more obvious for a genus change, but Cattle Egret is apparently a bit more removed from Ardea, and a case can be made that it should remain monotypic in light of the physical and behavioral adaptations for a more terrestrial lifestyle that make it most unque from its would-be co-geners.

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Revisit the proposed split of Circus cyaneus and Circus hudsonius

This is a re-submission of a proposal first submitted to the committee last year. Circus cyaneus is a holarctic species known as Northern Harrier in the Americas and Hen Harrier in the Old World. The two subspecies, hudsonicus in the New and cyaneus in the Old, are considered good species by all other relevant authorities in the world, but such a treatment has not been official in North America in nearly 100 years. This proposal adds to the 2015 proposal with a study examining morphological and genetic differences in the two populations, increasing the sample size from the previous refefinding significant distance between the two. If accepted, this would be yet another New/Old World split, which in recent years we’ve seen in Common Gallinule/Moorhen, Black/Common Scoter, and Snowy/Kentish Plover, among others.

Interestingly, this split would potentially add a new species to the ABA checklist, as wing from a presumed C. c. cyaneus was salvaged on Attu, Alaska, in 1999. C. c. hudsonicus is a rare vagrant to Great Britain and Ireland.

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Split Yellow-rumped Warbler Setophaga coronata into three species

At last, the split we’ve all bee sort of waiting for. Yellow-rumped Warbler consists of four subspecies, two of which, audubonii and coronata, are common and familiar species in the west and east, respectively, of the ABA Area. The other two, goldmanii and nigrifrons, are more or less sedentary residents of Middle America. Audubon’s and Myrtle Warbler were considered separate species for decades, before being lumped, along with the Middle American subspecies, by the AOU in 1973. I can’t go into detail about the evidence that is presented in this proposal, but it is sufficient to say that the evidence is robust. We have, after all, been talking about this split practically since the year the two birds were lumped. There is certainly a hybrid zone in British Columbia and Alberta, the the two subspecies appear to segregate themselves in a manner than is consistent with other species pairs considered to be heterospecific.The names Audubon’s Warbler and Myrtle Warbler continue to be used widely and would be resurrected. The nigrifrons subspecies of west Mexico would be included in the Audubon’s group, with goldmanii given full species treatment.

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Split the Willet Tringa semipalmata into two species

Along with Yellow-rumped Warbler, Willet is often on the short list of likely ABA Area splits though the species has never been treated that way in the past. Willet currently consists of two subspecies, semipalmata, called “Eastern” Willet, which breeds in coastal habitats in the southeast and winters primarily in the Caribbean and northern South America, and inornata, or “Western” Willet, which breeds in the interior west of the continent and winters along both coasts of the ABA Area. Birders have long noted morphological differences in the two groups, such that many field guides describe them separately, and recent research looking at the DNA of the two groups suggest significant differentiation between the two groups with little to no hybridization. The new species would be given the appropriate, if uninspired, names of Eastern Willet and Western Willet.

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Modify our treatment of juncos: (a) recognize bairdi as a species, (b) recognize alticola as a species, and (c) lump phaeonotus and hyemalis

This one looks more complicated than it is, despite the fact that it is generous to say that Junco taxonomy is muddy. First off, we can more or less disregard a) and b) as both of those subspecies occur south of the ABA Area – bairdi in Baja California and alticola in Guatemala. Both are currently considered subspecies of J. phoeonotus, or Yellow-eyed Junco, which occurs in the ABA Area only in southeastern Arizona. C is the important one for us, and, to be honest, it feels like a bit of an add-on. The genetic work that established that bairdi and alticola are distinct at the species level, which seems to be the main thrust of this proposal, also showed Yellow-eyed and Dark-eyed Juncos to be quite close. But, as the proposal itself states, the situation is complex and needs more work, which sounds to me like junco taxonomy in a nutshell.

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Change the linear sequence of species in Scolopacidae

We end as we began, with another proposal to re-organize a family of birds. This follows up an accepted proposal from last year involving shorebirds. If last year they shook up the box, this one is opening it and carefully moving a couple pieces. Nothing shocking here, just moving around some curlew and shanks.

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The full list, including background information and recommendations, is available here. We’ll have more once the decisions are published this summer.

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