Divers; Or Why I Don’t Get Invited to More Cocktail Parties

Hooded Merganser and Red-breasted Merganser

The scientific names of the saw-billed ducks lead in all sorts of interesting directions. Take the Hooded Merganser, possibly the loveliest of a very lovely group of birds; its current genus name, Lophodytes, is as pleasant to say as it is meaningful.

“Lophos” is from the Greek word for crest, and “dytes” means “digger, diver.” So our cute little hoodie is a crested diver, a point only reinforced by the specific epithet cucullatus, meaning, well, hooded, or cowled.

There are somewhere between many and gazillions of birds with loph- in their name somewhere, and cucullatus/a/um is nearly as frequent. The “dytes” part is more interesting. Two penguin species–the consummate divers–share the genus Aptenodytes, meaning “wingless diver,” and the name “troglodytes,” familiar even to many non-birders as the genus name of the mouse-like wrens, has also been applied to species and subspecies of nightjars, swifts, waxbills, and cisticolas, each of which typically (and sometimes maddeningly) disappears from the birder’s view by diving into the darkness.

The other bird in the photo above is a drake Red-breasted Merganser, Mergus serrator. “Serrator” is easy enough to figure out: like the English word “serrated,” it has to do with “serra” or “secra,” a toothed saw, in reference to the pointed projections on mergansers’ bills, which help them hold on their slippery prey. Oddly enough, “serrator” is rumored to also be an obsolete English name for the Ivory Gull–I don’t believe it, or even understand it, but such are the things one can run across on the internet.

Mergus, the genus to which all other mergansers but the Smew are assigned (and that’s simply Mergellus, a little teeny tiny Mergus) is a bit more mysterious. The word is obviously related to the Latin  “mergo,” “I dive,” on the same impulse as “dytes” (and the old genus name for the loons, Urinator).

But it is only recently that the noun “mergus” has been restricted in meaning to the mergansers. In Antiquity, the word referred to a number of ill-defined, perhaps unidentifiable waterbirds; Arnott notes that Pliny used “mergus” to translate Aristotle’s Aithyia, which is used nowadays (in a slightly different spelling) as the genus name for the pochards. To heap confusion onto mix-up, Arnott concludes (quite cogently) that Pliny and a few later Latin writers used “mergus” to denote the Great Cormorant, while in many other cases the name means simply “diving piscivore,” perhaps including Great Black-backed and Yellow-legged Gulls.

The name “merganser” (which doubles as the specific epithet of the Common Merganser or Goosander) is easily analyzed as a combination of Latin “mergus” and “anser,” meaning goose; it apparently first appeared in the neo-Latin of Conrad Gesner’s Historia animalium.

Gesner’s cut is plainly of a Common Merganser, but in its earliest English usage, the word “merganser” was explicitly restricted to the Red-breasted Merganser. Sir Thomas Browne wrote in 1668 that the “gossander… is a large well colored and marked diving fowle most answering [closely corresponding to] the Merganser.” It seems to have taken nearly two centuries for the name to be applied more generally to all the saw-bills–first, apparently, by MacGillivray in his History of British Birds. Charmingly and sensibly and perhaps slyly, MacGillivray suggested that the larger species be called “merganser” and the smaller “merganas,” “diving duck.”

The species names of most of the remaining Mergus mergansers are fairly straightforward. The extinct Auckland Merganser went by the name australis, “southern,” a reference to its range. Miocene miscellus, described from a Virginia specimen, shows a mixture–a miscellany, as it were–of primitive and derived characters, while the European Mergus connectens, a Pleistocene species, “links” other species. The Chinese, or Scaly-sided Merganser is named simply squamatus, “scaly.”

The critically endangered Brazilian Merganser has the most descriptive name of all its relatives. Mergus octosetaceus was named by Vieillot in 1817; the French name he gives it, harle à huit brins, reveals the meaning of the scientific epithet: this species, writes Vieillot, has a crest comprising eight narrow vaneless feathers.

Great name, that one; but eight years later, Vieillot, having discovered that the crest in other specimens was made of more than eight feathers, changed both the vernacular and the scientific name, this time giving it the equally logical but inestimably more colorless name brasilianus.

The change created a confusion that persisted for nearly a century, with various authorities going back and forth over the years between some form (often enough mangled) of octosetaceus and brasilianus/brasiliensis. In 1850, Pucheran proposed a new, or rather an old, epithet, lophotes, which he had discovered on the label prepared by Cuvier and attached to Vieillot’s type specimen in Paris; Pucheran also took the opportunity to propose for the first time the synonymization of Latham’s Mergus fuscus. But Pucheran’s new name was pushing the idea of priority too far, and Vieillot’s (inaccurate!) octosetaceus has prevailed.

Pucheran’s–or Cuvier’s–specific name for this rare bird takes us back to the beginning: “lophotes” means simply “crested,” from the same word that gave us Lophodytes. Next time you’re standing around balancing a drink and a horse doover, try some of this stuff out on the other guests: you may never have to worry about being asked out again.

By the way, who doesn’t love the Biodiversity Heritage Library? It’s impossible not to while away an entire day following even the most whimsical thread.