The Black Skimmer (Rynchops niger), is one of three very similar bird species in the skimmer family. It is found in North and South America. Northern populations winter in the warmer waters of Caribbean and tropical and subtropical Pacific coasts. The southern races only move shorter distances when threatened by the annual floods which extend their feeding regions.
The Black Skimmer is 15.5 to 20 inches long with a 42 to 50 inch wingspan. Males weigh about 11.5 ounces and the female weighs less at about 8.33 ounces. The inner part of the bill is red, the rest mainly black, and the lower mandible is much-elongated and flexible. The eye has a dark brown iris and catlike vertical pupil, unique for a bird. The legs are red. Breeding adults have a black crown, nape and upper body. The forehead and underparts are white. The upper wings are black with white on the rear edge, and the tail and rump are dark gray with white edges. The under wing color varies from white to dusky gray depending on region. Non-breeding adults have paler and browner upperparts, and a white nape collar. The call is a barking kak-kak-kak.
The Black Skimmer breeds in loose groups on sandy beaches and banks on the coast. Three to seven dark-blotched beige or bluish eggs are laid and incubated by both parents. Chicks leave the nest immediately after hatching and lie in the nest depression where they are shaded from the high temperatures by the parents. Sometimes they may dig their own depressions in the sand. Feeding occurs almost entirely during the daylight hours.
Skimmers have a light graceful flight, with steady beats of their long wings. They feed in often large flocks, flying low over the water surface with the lower mandible skimming the water for small fish or crustaceans, caught by touch by day or especially at night. They spend much time loafing gregariously on sandbars in the rivers, coasts and lagoons they frequent.