2016 AOU Check-list Proposals, Part 1

It’s time, once again, for split and lump season, or at least the first part of the long prelude to changes to your lists. The first document containing the proposed taxonomic updates to the AOU North American Check-list, which in turn are incorporated into the ABA Checklist, is out, containing the first 11 proposals that were submitted in 2015. Not all of them involve ABA-Area birds as the AOU’s North American jurisdiction includes Mexico and Central America to Panama’s southern border.

As usual, 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 please refer to the official list of proposals at the AOU’s website (.pdf).

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Elevate Aphelocoma californica woodhouseii to species rank

We start off with a split, one that has been on the short list of possibilities for some time. When the scrub jays were originally split into 3 in 1998 it was acknowledged that there was the potential for future split among the species known as Western Scrub-Jay. That widely distributed species consists of two subspecies, woodhouseii in the interior and the more coastal californica. The two differ fairly significantly in morphology, behavior, habitat preference, and genetics such that the proposal suggests finally splitting them into their own species. Notably, this isn’t the first time that this particular split has been proposed. It was proposed and failed a few years ago because the committee wanted more detailed information from the species’ narrow range of overlap, which this new proposal seeks to provide using two new studies completed in the interim.  The names Woodhouse’s Scrub-Jay (for woodhouseii) and California Scrub-Jay (for californica) are already widely used, and would apply to the new species.

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Adopt “Whitestart” as the English surname of species of the genus Myioborus

The genus Myioborus consists of three species of wood-warbler, only one of which, Painted Redstart, regularly occurs in the ABA Area. The birds are called redstarts despite the fact that the flashes in their tails (the “starts” from the Old English for tail) are white. More, redstarts generally refer to a group of unrelated Old World flycatchers in the family Muscicapidae. The proposal seeks to clarify taxonomic relationships (or lack thereof), more accurately describe the birds themselves, and bring the AOU name of the birds in line with a number of other authorities which already use whitestart in reference to Myioborus.

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Lump Common Redpoll Acanthis flammea and Hoary Redpoll A. hornemanni into a single species

Here it is. The one we’ve been expecting and dreading for years finally made manifest. There have been rumblings about a redpoll lump for several years. We published a more detailed look at the science here at The ABA Blog in 2013 (worth reviewing in light of this proposal), but the short version is that the differences between Hoary and Common Redpoll are more continuous rather than discrete. That means they occupy a continuum line from big pale Hoary all the way to small streaky Common with most birds falling between. This is in line with what field birders who have regular experience with the two have been saying for years. More, reports of Hoary and Common Redpolls sorting themselves by type where their breeding ranges overlap appears to be not well backed up. The proposal is remarkably thorough so we all may as well resign ourselves to the lump that seems to be coming. The only question is whether we retain Common Redpoll as the species name for the whole lot, or go full Euro and simply call them all “Redpoll”.

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Revise generic assignments of woodpeckers in the genus Picoides

As the genetic component of ornithology becomes more sophisticated, we’ve come to the frequent rearrangement of well-known groups due to new DNA analysis. This one is pretty neat in that it not only rearranges the old familiar Picoides genus, which were sorted into their current arrangement solely due to plumage similarities, but breaks these charismatic pied woodpeckers into four new genera with new insights into their relationships. Three of the new genera are relevant to ABA birders. The new arrangement retains Picoides only for Black-backed and Three-toed Woodpeckers, and resurrects the poetic Dryobates and Leuconotopicus. The former would contain the small Downy, Nuttall’s and Ladder-backed Woodpeckers, and the latter the larger Red-cockaded, White-headed, Hairy, and Arizona.

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Move Motacillidae and Prunellidae to the “core passeridans”

These two families are most diverse in the Old World but are represented in the Americas by American Pipit, Sprague’s Pipit, Eastern Yellow Wagtail and a number of vagrants.  Phylogenetically, both families have long been lodged firmly between Sturnidae (Starlings) and Bombycilidae (Waxwings), but this new work suggests they’re a better fit among the “core passeridans”, a groups that consists of finches and sparrows, among other primary Old World families. So, they’ll be further to the back of your field guide in the next editions.

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Change the linear sequence of genera in the family Odontophoridae

Here’s another genetic study that provides evidence to change the order of another family, this time New World Quail. The previous order was justified by little, so this proposal is certainly an improvement. As most of the effected species are found south of the Rio Grande, the only change ABA Area birders are likely to see is the movement of Northern Bobwhite (genus Colinus) to before the top-knotted quails (genus Callipepla).

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Merge Caribbean Coot Fulica caribaea into American Coot F. americana

Caribbean Coot used to be on the ABA Checklist, but was removed in 1991 due to doubts raised about the validity of records and the taxonomic status of Caribbean Coot. That thinking is behind this proposal to formally lump Caribbean Coot and American Coot, as the single inconsistent morphological difference (the white shield) is not enough to justify their status as separate species. This is particularly true as apparent American Coots with white shields are regularly seen across the range of the species.

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Revise the classification of the Caprimulgiformes

The strange goatsuckers in the order Caprimulgiformes are a hodgepodge of mostly nocturnal, mostly cryptic, mostly flying-insect eaters. In addition to the nightjars and nighthawks in the ABA Area, the order also consists of the bizarre Potoos and the Oilbird in the Neotropics and the puppet-like Frogmouths and Owlet-Nightjars in the Old World tropics. What the study that informs this proposal finds, however, is that families in the order are also very very old. In fact, they’re so old that they were largely differentiated 54 million years ago, long before other taxa that we regard as orders unto themselves.  This proposal suggests that we treat these disparate families as orders. The ABA Area Caprimulgids, however, would remain.

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The full list, including background information and recommendations, is available here (.pdf). We’ll have a look at subsequent proposals as they’re released.

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