Animalia Life

Rynchops niger
SUBFAMILY
Rynchopinae
TAXONOMY
Rynchops nigra Linnaeus, 1758, America. Species name changed from nigra to niger. Three subspecies usually are recognized.
OTHER COMMON NAMES
French: Bec en cisseaux noir; German: Amerikanischer Scherenschnabel; Spanish: Rayador Americano.
PHYSICAL CHARACTERISTICS
16–18 in (41–46 cm); male is 0.7–0.8 lb (300–375 g), female is 0.5–0.7 lb (230–300 g). Females considerably smaller than males. Black cap, back of neck, back, wings, and tail; white forehead, front neck, and belly. Nonbreeding adult has white nuchal collar and somewhat browner upperparts. Juvenile resembles nonbreeding adult.
DISTRIBUTION
Coasts of United States, Mexico, and south into Mexico, and in inland rivers of central and northern South America. Winters along coasts of California south to Chile, and from Caribbean south to northeastern Argentina.
HABITAT
Breeds mainly along coasts (and inland rivers in South America) on sandy beaches, sandbars, shell banks, dredge spoil islands, and also on wrack on salt marsh islands. Winters in inland rivers, estuaries and marshes, and mudflats. along coasts.
BEHAVIOR
Notably nocturnal in breeding
BEHAVIOR
and foraging. Mainly rests on colony site during day in breeding season. Territorial.
FEEDING ECOLOGY AND DIET
Has a unique foraging technique: forages by skimming the water with the lower mandible below the surface and the upper mandible above water. Skims for 82–328 ft (25–100 m) before rising in the air to circle back and skim again. Feeds mainly on fish.
REPRODUCTIVE BIOLOGY
Monogamous, and both sexes engage in territorial defense, incubation of the eggs, and chick care. Breeds from mid-March to May in Northern Hemisphere. Usually nests within colonies of other terns and small gulls but sometimes nests in large conspecific colonies (Texas). Sometimes performs distraction display but normally relies on the aggressive
BEHAVIOR
and mobbing of terns to protect its eggs and chicks. Lays two to seven eggs (usually three or four). Incubation period 21–26 days. Fledging period 28–30 days.
CONSERVATION STATUS
Not threatened. Breeding colonies often in conflict with recreationists and people living along sandy beaches. Eggs and young vulnerable to tidal flooding, human-enhanced predators (dogs, cats, foxes, raccoons), direct human disturbance, and egging. Riverine colonies in South America particularly vulnerable to flooding from heavy rains.
SIGNIFICANCE TO HUMANS
Although egging is rare in northern skimmers, much egging occurs in South America.

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