Caspian Tern Sterna caspia Pallas       Field Guide IDs: NG-214; G-154; PE-94; PW-pl 36; AE-pl 65; AW-pl 47; AM(II)-86 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy MF I: 20-22 DAYS SEMIPRECOCIAL MF 2-3 (1-4) MONOG F: 30-40 DAYS MF AQUATIC .....INVERTS BREEDING: Fiat sand or gravel beaches, shell banks, occ marshes. 1 brood. DISPLAYS: Courtship complex and variable includes aerial chases. NEST: Varies with location; eggs placed on rocks, in sand, or concealed among driftwood, shells, and rubbish. Lined with moss, grass, seaweed. Occ builds Up rim. EGGS: Pinkish-buff, marked with browns. 2.6" (65 mm). DIET: Hovers before diving for fish; also takes crustaceans. Occ pirate. CONSERVATION: Winters primarily in coastal bays, estuaries, lakes, marshes and rivers s to Colombia, Venezuela. Colonies often robbed of eggs in past. Human intrusion in breeding colony reduces reproductive success. NOTES: Usu small, occ large colonies, rarely solitary. Largest, strongest, fiercest, least gregarious tern. Usu breed at 4-5 years. Larger clutches in n. Pacific coast population (6,000 pairs in 1982) nests primarily on human-made habitats and shows 70% increase since 1960. Mate retention between years related to nest site stability, not to previous nesting success. Early nests more successful -- nest predation increases with season. Young recognize call of parents. Longest parental care known for terns: feed juveniles 5-7 months postfiedging. Flight gulllike. STANFORD. NOTES: ESSAYS: Parent-Chick Recognition; Coloniality; Site Tenacity. REFERENCES: Cramp, 1985; Cuthbert, 1985a, b; Gill and Mewaldt, 1983.