American Birding Podcast



2017 AOS Classification Committee Proposals, Part 3

Here is the third and likely last batch of taxonomic proposals, submitted in the last year to the American Ornithological Society’s North and Middle American Classification Committee. Part 1 is here. Part 2 is here. Proposals accepted by the AOC Committee are incorporated into the ABA’s Checklist.

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 we include them here because they are interesting and worthy of discussion.

This post will only mention those changes that affect the ABA Area, but if you’re interested in the whole ball of wax – the AOS NAMACC’s jurisdiction includes all of the North America south to Panama – please refer to the official list of proposals at the AOS’s website (.pdf).


Revise the linear sequence of genera in Fringillidae, and transfer Serinus mozambicus to Crithagra

This fairly straight ahead proposal rearranges the genera in the finch family based on a handful of recent phylogenetic studies. Serinus mozambicus, commonly known as Yellow-fronted Canary, is an established exotic in the ABA Area in Hawaii and a good candidate for inclusion on the ABA list. It moves to genus Crithagra along with a few Old World relatives.


Split Brown Creeper (Certhia americana) into two species

The New World’s lone representative of the treecreeper family, the unique Brown Creeper consists of two “groups” with more than a dozen named subspecies. The Northern Group contains the birds that most birders in the ABA Area are familiar with, with the Southern Group only creeping (you’re welcome) into the ABA Area in southeastern Arizona but occurring through Mexico into northern Central America. Birders and ornithologists have long noted differences between these two groups where they overlap, with northern birds being generally larger and lighter than the southern birds. The proposal is based on a study that looked at genetic differences between the groups and found them to be fairly significant, with little or no gene flow occurring. In fact, the “boundary” between the two groups seems to correspond with well-defined forest types, and is consistent with boundaries seen in other nearctic/neotropic species pairs. The proposal suggests the name Nearctic Creeper for the northern group, with Brown Creeper retained for the southern, mostly non-ABA, group, which seems unnecessarily confusing. The committee suggests Nearctic and Neotropical Creeper for the two.

Brown Creepers in southeast Arizona, like this one from Cave Creek Canyon in Cochise County, are quite different from those elsewhere in the ABA Area. Photo: Jay McGowan/Macaulay Library (S30887780)


Split Nashville Warbler (Oreothlypis ruficapilla) into two species

Nashville Warbler isn’t often among the increasingly short list of likely splits in the ABA Area, but the species does consist of two subspecies that, while similar in appearance, don’t breed anywhere close to each other. The eastern subspecies ruficapilla breeds across the northeastern United States and much of southeastern Canada west through Manitoba. The western ridgwayi subspecies, often known as Calaveras Warbler, breeds roughly from southern British Columbia into California. The proposal cites differences in morphology, behavior, and vocalizations, and genetic studies done in the not too distant past found significant distance between the two suggesting that even if their breeding ranges did overlap, they wouldn’t interbreed. The proposal suggests the established name Calaveras Warbler for ridgwayi, and the somewhat uninspired Rusty-capped Warbler for ruficapilla, noting that Nashville Warbler is a pretty lousy name for this species. Can’t say I disagree with that last part, at least.


Lump Thayer’s Gull (Larus thayeri) with Iceland Gull (Larus glaucoides)

This proposal has been simmering for some time, as many birders have long since come to the conclusion that these two species actually represent one near-hemisphere spanning cline, from the entirely white-winged nominate Iceland Gull of western Europe to the muddy-winged Thayer’s of the Pacific Coast. The proposal suggest that the entire premise for considering Thayer’s as a full species is flawed, at best, from the very source and the 1960s research that more or less informed that decision is called into question. In that case, the path of least resistance would require that, in lieu of genetic research on these birds, that Iceland and Thayer’s Gulls be considered one species. Another option, that nominate Iceland Gull and Thayer’s Gulls are full species in their own right, and that the bird we call “Kumlien’s” Iceland Gull, which breeds in eastern Canada and winters in the east of North America, is a hybrid swarm, does not seem to be taken into consideration by the proposal. But short of genetic samples taken from birds on their isolated breeding grounds, that question may never be answered.

Dark Iceland Gulls on the west coast, like this one from Monterrey, California, have always been problematic to identify. The AOS might make that question much easier, though no less interesting. Photo: Paul Fenwick/Macaulay Library (S33021659)


Change the spelling of the English names of Le Conte’s Thrasher (Toxostoma lecontei) and Le Conte’s Sparrow (Ammodramus leconteii)

This proposal seeks to correct a typographical injustice done to the John LeConte by none other than John James Audubon himself. Audubon was given the type specimen of the bird that came to be called Le Conte’s Sparrow but he neglected to enter the appropriate information at the time as he was recovering from a near-death experience, having shockingly very nearly shot himself in the head with a borrowed shotgun. Instead of a hole in his head, he put a hole in poor Mr. LeConte’s name in the monograph, where it stuck for nearly 175 years. The thrasher’s name was derived from the sparrow, evidently, and thus both were wrong. The proposal suggests that the names officially delete the space. To be honest, this whole thing was news to me, as evidently I’ve been spelling the names incorrectly (but now correctly) for years. Go figure.


Add Common Scoter (Melanitta nigra) to the Main List

Add Blyth’s Reed Warbler (Acrocephalus dumetorum) to the Main List

Add Chatham Albatross (Thalassarche eremita) to the Main List

Add Red-legged Honeycreeper (Cyanerpes cyaneus) to the U.S. list

These are house-keeping proposals of the type we see every year. As the ABA incorporates AOS taxonomic decisions into our list, the AOS incorporates documentation of new bird records per the ABA into theirs. These four species are added to their respective lists based on documented sightings. The scoter, warbler, and honeycreeper in California, Alaska, and Texas, respectively. The Chatham Albatross, originally seen in 2001, was re-evaluated by the California Bird Records Committee in response to the split of Shy Albatross some years ago and unanimously accepted.


Split Bell’s Vireo (Vireo bellii) into two species

Bell’s Vireo in the ABA Area consists of four subspecies split into two groups, roughly eastern and western. The two groups differ primarily in plumage and behavior, with differences in vocalizations often cited as well. The western group, often referred to as “Least” Bell’s Vireo has long been considered distinct, and is a conservation concern in California, Arizona, and New Mexico. The proposal notes that any change in taxonomic treatment of this group will have conservation ramifications. With that in mind, it’s surprising that it was not until recently that a full genetic study was done on this species, and the results were as expected with the two populations segregating genetically as well as spatially. The proposal suggests that the name Bell’s Vireo be retained for the population in the center of the continent, while Least Vireo is used for the endangered southwestern birds.


The full list, including background information, recommendations, and the whole log story about Thayer’s Gulls is available here (.pdf). We’ll post the results of the voting when we see them this summer.