Black Skimmer

Rynchops niger

(c) Glen Tepke
  • RHYNCHOPIDAE
  • Charadriiformes
  • Arador, Rayador
  • Bec-en-ciseaux noir, Bec à ciseaux (Louisiana)
Introduction
The Black Skimmer is distinctive for its unusual voice, brightly colored bill, and "skimming" behavior. When feeding, this coastal waterbird flies low, its long lower mandible slicing the water's surface in search of fish. The skimmer's long wings enable hairpin turns; flocks often wheel in unison. The bird's buoyant flight and dog-like barks inspired famed ornithologist R. C. Murphy in 1936 to describe them as "unworldly...aerial beagles hot on the scent of aerial rabbits."
(c) Margo Zrdravkovic
Appearance Description
Black Skimmers weigh about 11 ounces (300 grams), and measure 18 inches in length, with a wingspan of about 44 inches. Sexes look similar, with dark upperparts, a white forehead and underparts (juveniles are mottled brown above instead of black), a short white tail with black center, red legs, and a large black-tipped red bill. Black Skimmers are the only birds whose lower mandible is longer than the upper. Laterally compressed to cut through water like a knife, the bill is uniquely adapted to catch small fish. The skimmers' eyes have narrow vertical pupils, highly unusual in birds, which help reduce the glare from water and sand.
Range Map
Courtesy Kenn Kaufman
Range Distribution
Of the three races of Black Skimmer, the North American race is the only primarily coastal one, ranging along the Atlantic and Gulf coasts from Massachusetts to Texas, and through Central and South America. In the 1960s, Black Skimmers began spreading from western Mexico to southern California; they now nest in San Diego and the Salton Sea.
 
A legend for the range map to the right can be found here.
Habitat
Black Skimmers favor coastal waters protected from open surf, such as lagoons, inlets, sheltered bays, and estuaries. Local populations are found on inland lakes in Florida, and along California's Salton Sea. They nest on sandy beaches and islands.
Feeding
Black Skimmers feed primarily on small fish that live near the water's surface. As it flies, the bird's lower bill "skims" the surface of the water; upon contacting a fish, the upper bill snaps shut to catch it. This tactile feeding behavior enables the birds to forage by night, when waters are calmer and fish are closer to the surface. Black Skimmers are primarily crepuscular. They occasionally wade in shallow waters, foraging for fish and small crustaceans.
Reproduction
Black Skimmers are highly social birds, flocking outside the breeding season, and nesting in colonies on beaches and islands, often with aggressive gulls and terns that offer protection from predators. Colony sizes are highly variable, ranging from single pairs to many thousands on the Gulf Coast. The skimmer's nest is a shallow scrape on an open beach, shell bank, sandbar, and occasionally, a gravel roof. The three to five white, buff, or blue-green eggs, heavily marked with brown, are perfectly camouflaged on the beach.
 
The chicks, brooded and fed by both parents, hatch in about three weeks. They eat regurgitated fish and crustaceans dropped on the ground. Since chicks begin life with mandibles of the same length, they are able to retrieve this food; the lower mandible begins to elongate when chicks are nearly grown. Their unusual lower mandible grows faster than the upper mandible to compensate for the added wear received from skimming the water for prey. Parent skimmers defending nests may swoop low at intruders, uttering sharp, barking cries. Chicks soon begin to wander from the nest; they may hide when danger threatens by scratching out hollows, kicking up sand to partially cover, as well as cool themselves. The young birds begin to fly in about 24 days.
Migration
Black Skimmers withdraw from the northern part of their breeding range to winter in Mexico and Central America. They are sometimes pushed north of their usual breeding range, and more rarely, inland by tropical storms.
  • 165,000
  • 101,250
  • Moderate population declines, small population size
Population Status Trends
In the 1970s, the Black Skimmer was a declining, at-risk species; more recent evidence suggests many stabilized populations, although at lower levels than in the 1960s. Most data are from the late 1970s; censusing has since been irregular. Their status has varied from "Endangered" in New Jersey, to "Threatened" in New York, to "Species of Special Concern" in North Carolina and Florida, mainly due to loss of breeding habitat. In 1976, a key breeding population in the North Gulf Coast (Alabama to Texas) had about 15,000 pairs of skimmers in 37 colonies, primarily Louisiana. Along the Atlantic Coast, average colony sizes increase south of New England. Larger, denser colonies tend to be more stable and successful; small or failed colonies usually relocate for a second nesting attempt. Although the species' western range is expanding, both BBS and CBC data show population declines.
Conservation Issues
In the mid-1800s, skimmers, like most colonial waterbirds, were persecuted for their eggs and feathers. This greatly diminished Atlantic Coast skimmer populations; population size was estimated by the numbers of bushels of collected eggs. Some recovery occurred following protective legislation.
 
Currently, flooding, predation, and human disturbance are major causes of colony failure. Summer storms often flood nests, especially in early July, when tiny chicks are vulnerable. Development and increased human and dog traffic on beaches poses major threats to the skimmers' traditional nesting grounds. Even slight disturbances reduce nesting success. At some barrier beaches, off-road vehicles are a major threat. Early in the season, airplane noise causes skimmers to frequently take flight; they may later habituate. Egging by people of Asian descent, oil and chemical spills, and exploitation on Mexican and Central American wintering grounds pose other problems.
 
Protection of suitable breeding habitat is an ongoing challenge as human populations and their attraction to the beaches required by skimmers both expand. Large, stable colonies can be protected by preventing development, restricting off-road vehicles, fencing, educational signs, and wardens to prevent egging and disturbances. Ideally, skimmer populations should be monitored annually, via aerial surveys in each state. Banding of young skimmers should be extremely judicious, as it is potentially disturbing. The quality and quantity of fish stocks need monitoring and protection as well.
What You Can Do
Join beach cleanups in your area. Properly discarding of debris, particularly plastic, will prevent Black Skimmers and other waterbirds from eating it.
 
Don't discard used oil into city sewers or municipal water supplies. It can end up in the ocean where Black Skimmers rest and feed.
 
Dispose of kite string, monofilament fishing line, and plastic six-pack holders properly; both adult and young Black Skimmers can become entangled and killed in this debris.
 
Don't disturb nesting Black Skimmers when hiking or boating; prevent dogs and children from disturbing them as well. Black Skimmers are very sensitive to disturbance. When flushed from their nests, gulls and crows may take their eggs.
 
Make environmentally-friendly seafood choices, which helps protect the fish that Black Skimmers and other waterbirds depend upon. Learn more at http://seafood.audubon.org or http://www.mbayaq.org/cr/seafoodwatch.asp
 
For actions you can take, including Audubon activities, please visit our resources page.
More Information
 Visit our resources page for more information about this species.
Natural History References
Gochfeld, M. and J. Burger. 1994. Black Skimmer (Rynchops niger). In The Birds of North America, No. 108 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 
Kaufman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company, New York.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, Inc., New York, 2000
Conservation Status References
Gochfeld, M. and J. Burger. 1994. Black Skimmer (Rynchops niger). In The Birds of North America, No. 108 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.
 
Kaufman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company, New York.
 
Sibley, David Allen. The Sibley Guide to Birds. Alfred A. Knopf, Inc., New York, 2000