CLIPBOARD : BREEDING BIRD: BLACK SKIMMER (<i> Rynchops niger</i> )

Description: Most distinctive feature is lower mandible, which is longer than the upper portion (no other bird has this trait). Black back and crown contrast with white face and underparts. In winter, adults have a white collar around base of neck with duller color overall. Juveniles are mottled brown above. Long wings, red legs and red bill with black tip also stand out. Length: 18 inches. Wingspan: 44 inches.

Habitat: Found in salt marshes, shell banks, beaches and sandbars.

Diet: Shrimp, aquatic insects and fish.

Displays: In courtship, male attempts to overtake female while calling; each male briefly passes female with wing extended.

Nest: Scraped into mud or sand; unlined.

Eggs: Bluish-white buff with dark brown markings; 1.3 inches long.

Breeding-bird atlas: To report bird-breeding activity in your neighborhood, or to get information on the breeding-bird atlas, call Sea and Sage Chapter of the National Audubon Society members Sylvia Gallagher, (714) 962-8990, or Nancy Kenyon, (714) 786-3160.

Notes: Lower bill grows twice as fast as upper bill to offset erosion caused by skimming water surface for food. Never dives for food. Skimmers are the only birds to close the pupil into a vertical slit. Males incubate and tend young more than females, but females defend from predators and feed more than males.

Note: Map is divided into 5-kilometer squares so that Audubon Society volunteers can more easily survey areas on a regular basis.

Sources: Sea and Sage Audubon Society; “The Birder’s Handbook,” Ehlrich, Dobkin & Wheye, Fireside Books (1988); “Field Guide to the Birds on North America,” National Geographic Society (1987); “Birds of Southern California: Status and Distribution,” Garrett & Dunn, Los Angeles Audubon Society (1981).