Yes, we have no Pirangas
For those like me, who find the endless permutations of bird taxonomy both fascinating and frustrating, some interesting news from the American Ornithologists’ Union Checklist Committee, South American division. I can imagine that keeping track of the nearly 3500 (known) species of the Bird Continent can be overwhelming at times. I can attest, I was overwhelmed by only an afternoon I spent in Quito a couple years ago and I saw only around 25 of the nation’s 1600+ species, but this was largely because every five minutes I had to pull out the cinderblock sized Birds of Ecuador, rather ambitiously called a “Field Guide”, from my backpack. But I expect it can also be illuminating, as there are very few classes of life where the wonder and power of evolution through natural selection is so clearly visible.
For the most part, the actions of the South American committee rarely affect us North American birders though. They have plenty to deal with without handling our paltry 800 or so species. But a recent decision changes that, and throws into flux a group of birds many of us have a fair bit of experience with. Apparently, the birds we know as Tanagers, those in the genus Piranga, are not, in fact, tanagers.
The committee has moved the Pirangas, Western, Summer, Scarlet, Hepatic, the vagrant Flame-colored, and four others, to Cardinalidae, home of Cardinals, Grosbeaks, and Buntings, leaving birders in North America without a single representative from the famous neotropical family. At first it seems like an odd move, but sometimes the mtDNA that is behind these wholesale re-evaluations of bird taxonomy reveals to us that which is not clear on the surface, but obvious once you begin to look beneath the feathers. For those who have some experience with tanagers in the neotropics, it’s clear that the Pirangas are something a bit different. Their molt pattern and strong sexual dimorphism better matches those of Grosbeaks and Buntings, and their songs, warbly and complex, definitely sound more appropriate to the Cardinalids then the simple songs of the “true” tanagers. Van Remsen of LSU writes in the original proposal:
I am impressed by the overall phenotypic similarities in plumage patterns, subtle shades, and texture; these sort of fuzzy things don’t count for anything, of course, but I speculate that had earlier ornithologists not been so mesmerized by bill shape differences in their classifications and focused more on patterns and textures that the “new” Cardinalidae wouldn’t be so radical.
The question that affects most birders, however, is what to call a Tanager that is no longer a Tanager. The committee tends to prefer simply staying with “Tanager” in the same way there are some Buntings that aren’t Buntings (like Lark) or that both Tyrannidae and Muscicapidae are “Flycatchers” depending on where you are in the world. I suspect that nomenclature will stay the same, even as the birds in question migrate a bit further back in the books.
But an interesting suggestion that appeals to me was to call the birds by their genus name. For instance, we in the east would welcome the seasonal return of the Scarlet and Summer Pirangas while our friends out west would hear the rambling song of the Western Piranga each year. Even if 150 years of Tanager momentum makes a change so extensive unlikely, Piranga has a certain exotic charm, further reminding us of the connection these birds have to places and habitat far to the south. There certainly a precedent towards this sort of thing, genus turns to common names in the tropics with Euphonias and Saltators, or even our North American Anhinga.
Either way, it’s a revolutionary way to think about a familiar family, probably not the last rearrangement we’ll see in coming years as mtDNA continues to reveal the true nature of avian taxonomy.