Many of us in North America are facing the imminent departure of “our” hummingbirds for the next few months, though across the Gulf Coastal Plain, a few western hummingbirds are staking out winter homes, and hardy Anna’s Hummingbirds will do just fine along the Pacific Coast and in Arizona all winter long.
Rufous Hummingbird (Selasphorus rufus) wintering in Louisiana © David J. Ringer
Hummingbirds are one of the most distinctive and immediately recognizable groups of birds on earth. They’re also one of the most diverse, with approximately 330 species, all in the Western Hemisphere. But it was not always so: Ancient hummingbird fossils have been described from Europe in recent years, some with remarkable similarities (PDF) to modern New World hummingbirds, leaving scientists pondering the historical implications of these unexpected discoveries.
Hummingbirds have long been classified as most closely related to the widespread, well-known swifts and the treeswifts, a small, predominantly Indomalayan family. This group (the traditional order Apodiformes) is related to the weird, wonderful owlet-nightjars. This larger group is related to nocturnal birds traditionally placed in the order Caprimulgiformes (nightjars, potoos, frogmouths, oilbird, etc.), but their relationships and even the composition of this larger clade (called Cypselomorphae) is not settled (nighthawks, for instance, may be more closely related to owls than to nightjars). Update Sept. 17, 2012: See discussion in comments below.
As for the hummingbirds themselves, distinctive as the group is, the relationships within the large hummingbird family have been quite difficult to unravel. However, two recent papers by McGuire et al. (PDFs: 2007 and 2009) provide a framework for the current understanding of the hummingbird family tree, which as my title indicates is a pretty awesome place to hang one’s hammock and kick back for awhile. You know, maybe a millennium or two.
Topazes and jacobins
McGuire et al. found that four South American hummingbird species – the Florisuga jacobins and Topaza topazes – go together at the base of the hummingbird tree, challenging the orthodoxy that living hummingbirds belong in two subfamilies: the hermits (Phaethornithinae) and everything else (Trochilinae). They note, however, that further study is needed and that despite their genetic results, topazes and jacobins may more likely be sister to all other hummingbirds except the hermits. In any case, this is a small but spectacular group of birds. Check out this Crimson Topaz. And this one.
White-necked Jacobin (Florisuga mellivora) in Ecuador © David J. Ringer
The hermits are a distinctive group of hummingbirds, most with strongly curved bills (most pronounced in sicklebills), subdued colors, and lekking displays by the males.
Tawny-bellied Hermit (Phaethornis syrmatophorus) cc-by-sa Michael Woodruff
This group contains several fairly large and spectacular species, including the violetears, caribs, and mangoes, which are well represented in the Caribbean, as well as unique South American jewels, such as the Horned Sungem.
Green Violetear (Colibri thalassinus) in Costa Rica © David J. Ringer
This group and the next (the brillants) together are called the Andean clade and indeed reach their highest and most mind-blowing diversity in the mighty Andes. They are tiny but often highly ornamented species, sporting some of the most breathtaking head and tail plumes in the entire hummingbird tree. Take, for instance, the absolutely incredible Frilled Coquette). In the Andes, species such as Wire-crested Thorntail, sylphs, sunangels, hillstars, thornbills, and metaltails light up the forest.
Violet-tailed Sylph (Aglaiocercus coelestis), Refugio Paz de las Aves, Ecuador © David J. Ringer
The brilliants are a diverse group that includes the pufflegs, sunbeams, incas, starfrontlets, coronets, and brilliants proper, as well as the huge and magnificent Great Sapphirewing and Sword-billed Hummingbird, which is the only bird with a bill longer than the rest of its body. The brilliants are some of the most colorful and abundant hummingbirds of the Andes, and Mike and I enjoyed a great many of them when we toured the Ecuadorian Andes with Renato and Paola in 2010. Here are two:
Velvet-purple Coronet (Boissonneaua jardini), Refugio Paz de las Aves, Ecuador © David J. Ringer
Booted Racket-tail (Ocreatus underwoodii) in Ecuador © David J. Ringer
The Andean Giant Hummingbird – truly a giant at more than 8 inches long! – is unique and is sister to all other remaining hummingbirds. It’s one that has eluded me but that I’m very eager to see someday.
The mountain-gems, starthroats, and their relatives are a predominantly Central American and Mexican montane clade, a few of which (Blue-throated Hummingbird, Magnificent Hummingbird, and Plain-capped Starthroat) just barely make it into the United States.
Magnificent Hummingbird (Eugenes fulgens) in Costa Rica © David J. Ringer
Bees are small to very small hummingbirds, including Cuba’s Bee Hummingbird, the smallest bird in the world at about 2 inches long and weighing less than a dime (!). Bees also include the woodstars and many of the regularly occurring hummingbirds in the United States and Canada, including the widespread Ruby-throated, Rufous, and Anna’s Hummingbirds and their relatives. Thus, this group also contains the most highly migratory hummingbirds in the world. Some travel thousands of miles per year.
Ruby-throated Hummingbird (Archilochus colubris) © David J. Ringer
And finally, we reach the emeralds, a large and widespread group of more than 100 species (about a third of all living hummingbirds), including the emeralds, sabrewings, woodnymphs, “Amazilia” hummingbirds, sapphires, the gorgeous Snowcap, and – in the United States – southwestern specialties like White-eared, Broad-billed, and Buff-bellied Hummingbirds.
Andean Emerald (Amazilia franciae) in Ecuador © David J. Ringer
Rufous-tailed Hummingbird (Amazilia tzacatl) in Ecuador © David J. Ringer
Want to stay awhile?
And there you have it. But if you’re hungry for more hummers, check out James’s Twenty Hummingbirds post (see how many of his hummers you can place correctly in the tree) and, if you’re feeling geeky, check out John Boyd’s hummingbird taxonomy and tree (PDF).
Sapphire-vented Puffleg (Eriocnemis luciani) in Ecuador © David J. Ringer