Ah, emerald! That brilliant beryl, birthstone of May and the most valuable gemstone, by weight, in the world, shines with a green so pure and bright that only the most verdant lands dare claim its name. The color emerald looks as fine in a feather as it does in a jewel. In Central and South America, you’ll find a gorgeous Toucanet and Tanager with emerald in their titles. The Old World boasts two doves of exceptional taste, the Emerald Dove of Australasia and the Emerald-spotted Wood-Dove of Africa. But emerald, like all jewel tones, favors hummingbirds best.
Hummingbirds dappled by this gracious green include Emerald-bellied Puffleg, Emerald-bellied Woodnymph, and Emerald-chinned Hummingbird, beautiful birds every one. But emerald also bears the distinct honor of being one of only two colors (sapphire is the second) for which birds are actually named. There are no fewer than 27 emeralds scattered like glittering gems throughout four genera of the family Trochilidae.
The genus Chlorostilbon, widespread throughout the Neotropics and West Indies, contains the bulk of the emeralds, with Golden-crowned, Cozumel, Canivet’s, Garden, Glittering-bellied, Chiribiquete, Cuban, Brace’s, Gould’s, Hispaniolan, Puerto Rican, Coppery, Narrow-tailed, Green-tailed Emerald, and Short-tailed to its credit. Dimorphic as most hummingbirds are, birds in this genus all follow the same fashion – males with sparkling green throats and breasts, females dull ash. The two Elvira emeralds, White-tailed and Coppery-headed, are equally iridescent and enchanting. Emeralds in Agyrtria, including Plain-bellied, Versicolored, Rondonia, White-chested, Andean, and White-bellied, and Polyerata, with Sapphire-spangled, Glittering-throated, and Honduran, tend to exhibit more similarity between the sexes than is typical for hummingbirds. Similarities between the two genera are expected, as both were once part of Amazilia. Not that the taxonomy of these natty nectarsippers is anywhere near as fascinating as their prismatic plumage!
Emerald is hardly the only green gem to bejewel birdlife. The Tourmaline Sunangel combines exquisite amethyst and deep forest green, while the Berylline Hummingbird mixes chestnut and kelly to remarkable effect. Malachite is another flattering hue in birds, as anyone who’s seen the Malachite Sunbird can attest. Africa’s Malachite Kingfisher may be a more familiar example of a bird named for this striated green mineral, but in this instance, malachite seems a misnomer. More likely, the blisteringly blue kingfisher was identified with the mineral azurite, which often appears with malachite.