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BOU splits with AOU relevance

The British Ornithologists' Union Taxonomy subcommittee recently released their annual recommendations report for 2011 (.pdf), and while the most of what goes on in the birding scene in Great Britain operates independent of those of us here in North America, there were a couple splits that could be predictive of potential new species in the AOU and ABA areas. 

First though, the BOU mirrored the recent decision by the AOU to separate the Palearctic Kentish Plover, Charadrius alexandrinus, and its Nearctic counterpart, Snowy Plover, Charadrius nivosus, but they didn't stop there.  Two additional members of order Charadriiformes got pared off as well. 

Whimbrel, Numenius phaeopus, was also split along hemispheric lines, with the white-rumped Old World group officially becoming Eurasian Whimbrel and retaining the scientific name, and our dark-rumped North American birds regaining the storied name, Hudsonian Whimbrel, Numenius hudsonicus.  If accepted by the AOU, this would represent a new species for North America, as 'Eurasian' Whimbrels are regularly noted on the east coast and generally offer little in the way of identification pitfalls.

CabotsTern More interesting is the split of Sandwich Tern, Thalasseus sandvicensis, into the Eurasian population that retains the name famously referring to the English town rather than the lunchtime treat, and the North American acuflavida and eurygnatha subspecies, to now be known, according to the BOU, as Cabot's Tern. 

Recent molecular analyses suggests that the New World population, Cabot's Tern, is actually more closely allied with Elegant Tern than the nominate subspecies, and therefore the split is in order.  Additionally, differences were noted in all plumages between North American and Eurasian birds; differences that European birders are no doubt poring over in the wake of this decision.  North American birders would do well to bone up similarly, as Sandwich Tern (Eurasian Sandwich Tern now?) is a likely stray to our shores. 

It remains to be seen whether the AOU tackles these splits as well, as they seem to be a little more conservative when it comes to Old World/New World splits.  They'll no doubt consider them in upcoming years, and the recent separation of Common Moorhen and Snowy Plover may well portend a wave of such taxonomic changes, in which case this BOU decision is only the beginning and birders might want to bank their armchair ticks in preparation.  

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Nate Swick

Nate Swick

Editor, Social Media Manager at American Birding Association
Nate Swick is the editor of the American Birding Association Blog, social media manager for the ABA, and the host of the American Birding Podcast. He lives in Greensboro, North Carolina, with his wife, Danielle, and two young children. He is the author of Birding for the Curious and The ABA Field Guide to Birds of the Carolinas.
Nate Swick

Latest posts by Nate Swick (see all)

  • This is great, Nate, thank you; I hadn’t had a chance to read the BOU report yet, and this introduction will help tremendously.

    A humorous note: I first read the title of this entry as containing a verb, and wondered what comment you might be making on the AOU Check-list C’ee.

  • What is “Geokichla”? Is it intended to be separate from Geocichla?

  • jmj

    Heh, I read the headline in exactly the same way as you did.

  • The stonechat discussion here is one to follow, too.

  • As Rick said, thanks so much for calling this to our attention, Nick.

    We should hope that someone formally proposes these to the AOU Check-list Committee for consideration.

    A housekeeping note: At this point the splits are recommendations by the Taxonomic Subcommittee of the BOU Records Committee. They won’t take effect for The British List until the BOURC votes on them and then publishes its decisions in the BOU’s journal Ibis.

    For me, it would be nice to welcome back Cabot’s Tern, which sparks childhood memories for this ol’ geezer. I don’t think I’ve seen that name in a field guide since my 1940s edition of the eastern Peterson, which I started using at about age 8 (in the far West, where there were no Cabot’s Terns!) and which is now held together with duct tape.

  • The Sandwich Tern article cited is apparently on line in Dutch only. I’ve quickly translated it at

  • It’s funny how you can write something and be completely oblivious to any other interpretation other than the one in your head at the time. Now that you mention it, it’s obvious, but no commentary to that end…

  • What fast service, Rick! Thank you.

    Incidentally, Nate, I didn’t call you Nick to rhyme with Rick. I had just sent a note to a guy named Nick and wrote it again mindlessly. Sorry.

  • Ned Brinkley

    I don’t think they’ll call the bird “Eurasian Sandwich Tern” – probably just Sandwich Tern and ‘our’ Cabot’s Tern. If the split happens. I have zero plans to search for Sandwich Terns! Worse than looking for Little Terns among Leasts!

  • No worries, Paul!

  • Aht Hahs Dave

    We used to see limmerels aht on Presque Isle during migration.

  • If I’m reading it correctly, Eurasian Whimbrel are (will be?) found regularly in western Alaska too.

  • J. V. Remsen

    Concerning the Whimbrels and the Sandwich Terns, note that the BOU is basing this on a single gene tree — the branching pattern shown by a single gene. We are learning the hard way that “gene trees” and “species trees” are not necessarily the same thing, as dramatized by Jacobsen and Omland’s recent paper on North American orioles and Carling and Brumfield’s paper on Passerina buntings. Therefore, bar is being raised rapidly on using single gene trees to change classifications. Also, note that the BOU seems to be applying “bar-coder” logic to these decisions, namely if two taxa differ by more than a certain % sequence divergence, then they are ranked as species. That logic is widely disputed, at least here in North America. As for the Whimbrels, the last I heard was that calls are indistinguishable — is there any new data on this? If not, then I think they would be the only shorebird species pair that is not diagnosable by calls … if correct, highly suspicious.

  • I’ll just echo what Paul said. He pointed out the same to me just a few days ago. Check out the first couple paragraphs and the title of the article.

  • Kent Fiala

    Has there ever been a Hudsonian Whimbrel before? I believe that the “storied name” was Hudsonian Curlew.

  • You’re right! I stand corrected. Half storied, then.

  • Richard Klim

    Concerning Paul’s and Michael’s caution re ‘recommendations’. In practice, this seems to to be little more than a formality. The recommendations of all six previous TSC reports have been adopted by BOURC.

    See BirdForum for more discussion:

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