There are five subspecies of Black-necked Stilts (Himantopus himantopus). The American Ornithologists' Union calls the American version Himantopus mexicanus and internationally it is called Himantopus himantopus mexicanus.

Black-necked Stilts are found in North and South America. They are fairly common in the San Francisco Bay Area where they breed.

Sexes are similar but females are recognizable because their backs are brownish instead of black. Black-necked Stilts will flock together except when roosting. Then they spread out. They work together to discourage predators.