Skimmers are the only birds in the world whose lower bill is longer than the upper. The black skimmer pictured is 16-20 inches (40-50 cm) long with a wingspan of 3.5-4 feet (1.1-1.3 m) but weighs only 9-13 oz (250-370 g). Its bill is bright red-orange with a black tip, knife-thin from the side.
The bird is black above and white below with very long, pointed wings and short red legs. Skimmers are also the only birds with vertical, cat-like pupils, which shrink to slits in bright sunlight on the open beach and open wide for fishing at dusk.
There are three species: the black skimmer of the Americas, the African skimmer and the Indian skimmer.
Skimmers live on sandy beaches, estuaries, lagoons, salt marshes and large slow rivers. The black skimmer is found on the Atlantic, Gulf and Pacific coasts of the Americas and along the rivers of South America.
They nest in shallow scrapes on open sand and shell, often in colonies with terns.
Skimmers feed in a way no other bird does. Flying low and steady, the bird slices the surface with its lower bill. When it touches a small fish or shrimp the bill snaps shut and the head jerks down, all without the bird slowing. They feed mostly at dawn, dusk and night, when fish rise to the surface and the water is calm.
Skimmers rest on beaches in tight flocks, all facing into the wind, and take off together in swirling clouds. Their calls are short barks, like a small dog.
Pairs raise two to five chicks on the open sand. Chicks hatch with upper and lower bills of equal length and only grow the long lower bill as they learn to fly and feed.
The three skimmers make up the genus Rynchops in the family Laridae, alongside gulls and terns. The IUCN lists the black skimmer as Least Concern, the African skimmer as Near Threatened and the Indian skimmer as Endangered.
Because they nest on open beaches and sandbars, skimmers are easily disturbed by people, dogs and vehicles, and their nests are flooded by storms and rising seas. Many colonies are now fenced off during the breeding season.
