By BILL CHAISSON
Of a Feather
I saw a solitary vireo earlier this week for the first time in many years. The species is no longer called the “solitary vireo” but I persist in thinking of it that way. The American Ornithological Union holds meetings at intervals to decide the official vernacular names of birds, which is a bit of an oxymoron, but there you have it. Perhaps because it is such a popular pastime for the general public, there isn’t a strong tendency to call birds by their “real names,” that is, use the binomial nomenclature.
The real name of the vireo in question is Vireo solitarius, which is closer to the “common” name than is usual. The American robin, for example, is Turdus migratorius. The example of the robin is a good illustration of why these names are used. The real name of the European robin is Erithacus rubecula. The American bird is in an entirely different family, Turdidae, from its namesake, which is part of the Muscicapidae. Both families are in the order Passeriformes, but are not closely related.
Karl Linné, the 18th century Swedish naturalist, established the rules for the binomial nomenclature. Overall the it is a system of nested groups, like professional baseball. Genera are part of families that are part of orders in the same as teams are part of divisions that are part of leagues. The binomial is set up like a Chinese name, with the group name first and the individual name second. Turdus migratorius is part of a genus that includes Turdus rufopalliatus, the rufous-backed robin, a Mexican species that is seen occasionally in the southwestern U.S.
The rules of Botanical Latin are a bit different from those of Classical or Ecclesiastical Latin, but if you took Latin in school (as I did), using Latin names comes rather easily. In my own former field of research, micropaleontology, I was a philosophically a lumper, so I never named any new species myself, but should I have been so inclined, there would have been rules to follow. Unfortunately (or perhaps inevitably) these rules are regularly broken. The binomial of the European robin, for example, is irregular. Latin has declensions that assign gender to nouns and their adjectives. Erithacus is masculine (the -us ending), while rubecula is feminine (the -a ending), while according to the rules the genders should agree, as in Turdus migratorius.
The binomial nomenclature of birds has changed several times in the last 30 years, in large part because of advances in molecular biology that have used DNA to determine relatedness among species. Without even looking at the changing names, the varying order in which you find birds listed in guidebooks is in part due to the author’s acceptance and following of a certain taxonomy. (Taxonomy, by the way, is philosophy of relatedness, while systematics is a description of relatedness according to a particular taxonomy. Fun, huh?)
I grew up a Peterson’s field guide user and I am still used to that order of presentation. The vireos, in that scheme, come immediately before the wood warblers. In the early to mid- 20th century relatedness was based on appearance. Vireos and warblers do resemble one another in both appearance and behavior, so they were thought to be closely related. If you look at Sibley’s field guide they aren’t anywhere near each other.
Generally, the order represents a sequence from more basic to more derived groups. It is important to avoid words like “primitive” or “advanced” because there is no progressive assumption in evolution. Some groups like waterfowl are thought to share more traits with ancestral species and therefore are placed earlier in the order. This doesn’t mean that ducks are primitive compared to vireos and wood warblers. It means that in order to persist as species they simply have made fewer changes to distinguish themselves from preceding taxa.
Because the binomial nomenclature was invented by Europeans in Europe and used among people for whom Latin was a lingua franca. Last week I wrote about the American woodcock. Its genus name, Scolopax, is the Latin and ultimately the ancient Greek word for snipe or woodcock, both of which are present in Europe, so the naturalists simply used the ancient vernacular name as the scientific name. The purpose of the scientific nomenclature is to have one name that everyone knows and accepts.
This is expressly to combat confusion that arises when each country or even region develops their own tag for the same animal. In Denmark the woodcock is the skovsneppe, which translates to English as “forest snipe.” In France the woodcock is bécasse, which translates as “having a long beak.” In the U.S. there are many regional vernacular names for the bird, including timberdoodle, bog sucker, night partridge, brush snipe, hokumpoke, and twitterpate.
In contrast, the woodcock is Scolopax minor all over the world. It is smaller than the Eurasian woodcock, Scolopax rusticola, which was of course named first. Hence the “minor” as a species or trivial name. If the American species had been larger, it might have been called Scolopax major.
Which brings me back to the solitary vireo. Its genus name is some conjugation of the Latin virere, to be green. And indeed, all species of vireo are greenish, often washed with yellows and grays. None of the vireos are particularly social, so how the solitary vireo got its name, I don’t know. In any case, it has not kept it. It is a member of a group of three similar-looking vireo species, the plumbeous (i.e. lead-colored), the Cassin’s and the blue-headed, until the 1950s. During that period the American Ornithological Union seems to have gone through a lumping phase and based on morphological data, the three were combined to create the solitary vireo. In 1995 they were split up again based on new molecular data that showed that they did not in fact regularly interbreed.
The blue-headed vireo was called Vireo solitarius before the 1950s. It was named by pioneer ornithologist and bird painter Alexander Wilson in 1810. Between the 1950s and 1995 the scientific names V. plumbeus and V. cassinii were effectively put in a drawer. When molecular data ratified their validity, they were simply taken out of the proverbial drawer and given back to the species. And the solitary vireo as a vernacular name was thrown out and blue-headed vireo was brought back. But I still can’t get used to it.
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