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Ashy and Black-tailed

July 5, 2011

Until relatively recently, every species of gull from the brutish white-headed Great Black-backed to the dainty black-headed Little could be found in the genus Larus.  One only has to glance at a field guide to see that lumping this particular combination of birds into one catch-all box was a matter of convenience rather than taxonomic specificity, but the name Larus was a good one for this singularly representative sea bird.  Larus is latin, but derived from the Greek laros, meaning simply sea-bird.  Simple, effective, and perhaps the origin of that ultimate designation between birder and non, regular use of the much mocked term “seagull”.

When the gull genii were split in the mid 2000s following a genetic survey the 50 to 60 species shook out in roughly the way you’d expect.  The big white-headed gulls all stayed in the genus Larus, but the others spun off with other names, renewing long forgotten taxonomic categories; the bizarre Swallow-tailed Gull into Creagus, the tern-like Kittiwakes to Rissa, the enigmatic, arctic Ross’s and Ivory Gulls into Rhodostethia and Pagophilia respectively.  It was a sea change for Laridae that better represented the impressive diversity of this charismatic and familiar family.  Almost too familiar.

Gulls are one of the few families of bird that non-birders are aware of, if for no other reason than as the soundtrack for hundreds of summer beach vacations.  I’m fairly certain that beachgoers in North Carolina are completely unaware that the prevalent species on the beaches in winter are not the same as in summer.  Winter gulls here are primarily Ring-billed Gulls, classic white-headed Larus gulls if a bit on the small side for that genus, while those in the summer are something different entirely, gulls formerly known as Larus.  A new genus that is a hodgepodge of white and black headed species.  These birds of summer are the sleek black-headed Laughing Gulls, Leucophaeus atricilla.

It’s a shame that Laughing Gulls are so common, because they’d easily be on the short list of any birder’s favorite gulls if you had to work a little harder to find them.  The deep slate gray mantle and primaries not marred by white tips is a clean look. The black head is always a crowd-pleaser, but paired with that deep red bill and smart white half-arcs around the eyes it looks like a clown in negative.  And not one of those freaky clowns either, but a classy one like in an Italian arthouse movie.  This is a gull that looks good and knows it.

The genus Leucophaeus roughly translates to dusky white, or ashy.  Leuco- is recognizable, derived from the Greek leukos, or white.  -Phaeus comes from phaios, meaning dusky.  The genus is a hodgepodge of species that are obviously related, Laughing Gulls and the very similar Franklin’s and Galapagos endemic Lava Gulls, and a couple others that seem to be odd fits, namely the strange, heavy-billed and white-headed Dolphin Gull of South America.  Perhaps it’s appropriate, then, to chose such an unoffensive and broadly appealing genus.  Gulls are dusky, from the pale to white mantles of the white-wings to the coal black of a Greaterback, “dusky”, in that it can apply to any shade darker than white, is as appropriate as any.

It’s the species name where the fun starts. Atricilla is an odd choice for this particular gull, or any for that matter.  The first part is fine, from the Latin ater, or black.  There’s scarcely a gull around that doesn’t have some black in it’s plumage somewhere, be it the head of the Laughing Gull or the wingtips of many species around the world. It’s the cilla that’s completely wrong, because it’s from the Latin for “tail”.  Because if there’s one part of the Laughing Gull that isn’t black, that’s it.

How could this mistake have been made?  There are a couple theories, both based back in the heady early days of ornithology and concerning the father of taxonomy himself, Carolus Linneaus.  The first suggests that Linneaus meant to use atricAPillus but misread his own notes.  The inclusion of those two all important letters in the middle of the epithet changes the meaning from “black tail” to “black head”, an altogether more fitting name for our Laughing Gull.  But Linneaus was nothing if not a careful and studious individual, and this seems to me to be fairly unlikely that he would make such an egregious error.

The more likely explanation, at least to me, concerns the original description and illustration of Laughing Gull, done by the English naturalist Mark Catesby in 1731.  That painting, while mostly accurate, shows the adult Laughing Gull with a clearly darkened tail.  Not black by any means, but not white either.  Going by this illustration, Linneaus would have perhaps been justified to assume that the Laughing Gull was a black-tailed gull, a field mark not seen in any other known North American Larid and therefore likely to appeal to the great naturalist in naming the species.

We’ll never know for sure what happened, but what is known is that the Laughing Gull has the most obviously incorrect scientific name of any in its family.

But that only makes it more interesting, right?  Common though it may be, it still holds surprises.  No simple “seagull”, this one.


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