New York Natural Heritage Program
Black Skimmer
Rynchops niger Linnaeus, 1758
Birds

Identifying Characteristics [-]
The Black Skimmer is a medium-sized bird 45-60 cm in length with a long wingspan averaging 112 cm (Peterson 1980; National Geographic Society 1999). They are easily identified by their unique bill, with the lower mandible being longer than the upper. Adults in breeding plumage are black from the top of the head down the neck, back, and wings to the base of the tail. The forehead, cheeks, foreneck, tail, underparts, and edges of the secondary feathers of the wings are white. The bill is hinged and laterally compressed. The lower mandible is longer than the upper one. The base of the bill is red-orange while the rest of the bill is black. The legs are skinny and red. The dark-colored eye is surrounded by black feathers, making it appear invisible. Adults in nonbreeding plumage have a white collar around their neck and their black coloration changes to dark brown. Males and females are similar in color but the female is significantly smaller than the male. Juveniles resemble adults during nonbreeding plumage but are mottled brown on top and their bills are shorter, with the base being orange-red and the rest black. Hatchlings are semi-precocial and covered with down. They are mostly gray on top and pure white on the bottom. The lower and upper mandibles of the bill are even in length (Gochfeld and Burger 1994). Eggs are round to oval in shape, average 45 by 34 mm in size, and are pale cream to light green in color with brown speckles in various shades. Eggs that are laid down first are darker in color than those that are laid down last (Bent 1921). Nests consist of a scrape in the sand about five cm deep and 25 cm in diameter. No vegetative material is added. The call of the Glossy Ibis sounds like a series of barking yips (Gochfeld and Burger 1994).

Characters Most Useful for Identification [-]
Black Skimmers can easily be identified by their scissor-shaped bill which also has the lower mandible being larger than the upper mandible.

Best Life Stage for Proper Identification [-]
Black Skimmers can be easily identified when the adults are in their breeding plumage.

Behavior [-]
Black Skimmers are colonial nesters and often nest among terns and gulls. The birds arrive at their breeding grounds in late spring with pair bonds already established. Both male and female create nest scrapes and eggs are laid seven to ten days later, with one egg being laid per day until a full clutch of 3-5 eggs is down. Black Skimmers will renest several times if the previous nest is destroyed. The incubation period lasts 21-25 days with male and female taking turns. Hatching is asynchronous and occasionally results in mortality of younger chicks (Erwin 1977; Gochfeld 1978; Gochfeld and Burger 1994). Black Skimmers are active day and night and often feed at night during low tide. They are typically solitary feeders, rarely feeding in flocks (Bent 1921; Erwin 1977). There have been a few inconsistencies as to how they capture their prey. Arthur (1921) studied their feeding behavior and noticed that Black Skimmers rarely caught prey while skimming across the surface of the water and extending their lower mandible into the water to catch fish. He observed the birds foraging while standing in shallow waters by plunging their bill straight down and grabbing their prey. Later studies indicated that skimming indeed is the preferred method of prey capture (Tompkins 1951).

Diet [-]
Black Skimmers feed mainly on small fish but will sometimes forage for shrimp and other small invertebrates and crustaceans (Bent 1921; Leavitt 1957; Erwin 1977).
Black Skimmer Images
click to enlarge
The Best Time to See
In New York, Black Skimmers arrive at their breeding grounds in mid-April and remain throughout the breeding season. They begin their fall migration to their wintering grounds in late fall but have been known to congregate in flocks until mid-December (Gochfeld and Burger 1994).
J F M A M J J A S O N D
Present Breeding
The time of year you would expect to find Black Skimmer present (blue shading) and breeding (orange shading) in New York.
Similar Species
  • American Oystercatcher (Haematopus palliatus)
    The bill of the American Oystercatcher is all red in color and the mandibles are even in size. The wings are shorter. Oystercatchers have a white tail patch and a brown back with a white stripe going down the wings, visible when the wings are open. Black Skimmers do not have a white tail patch, they have a black back, and no stripe on their wings (Peterson 1980; National Geographic Society 1999).