The Black Skimmer (Rynchops niger) is one of the America’s most distinctive waterbirds, and one of three skimmer species found worldwide. Three subspecies are currently recognised, mostly based on distribution and migration patterns. In the past, it has had cool names such as Scissorbill, Shearwater, Seadog, Cutwater and even Razorbill.
This big black and white tern-like bird is noted for its unusual voice, bill, and feeding behaviour. Its bill – brightly coloured, laterally compressed, and knife-like, with the lower mandible extending beyond the maxilla – is uniquely adapted to catch small fish, insects, crustaceans, shrimps and molluscs in shallow water. A feeding skimmer flies low over the water in a distinctive bouncy style with its bill open and its lower mandible slicing the surface. When the mandible touches a fish, the upper bill (maxilla) snaps down instantly to catch it. They can even do this at night with almost no light around! They utter a nasal, hollow, laugh-like bark: “kyuh” or “kwuh”.
The Black Skimmer breeds in loose groups and colonies on sandbanks and sandy beaches in the Americas, with the three to six eggs being incubated by both the male and female. Although the mandibles of the newborns are of equal length at hatching, they rapidly become unequal during fledging.
They are highly social birds and spend much time loafing gregariously in large flocks on sandbars in the rivers, coasts and lagoons they frequent.