Herring Gull Supersp #15 Larus argentatus Pontoppidan       Field Guide IDs: NG- 202; G-144; PE-86; PW-pl 33; AE-pl 37; AW-pl 18; AM(II)-58 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy MF I: 24-28 DAYS SEMIPRECOCIAL CLIFF TREE < 60 feet MF 3 (1-4) MONOG F: 35 DAYS MF SURFACE DIPS HIGH DIVES BREEDING: Rocky terraces, grassy hummocks on sandy coasts, tundra, lakeside cliffs, grassy islands, salt marsh. 1 brood. DISPLAYS: Complex soliciting; courtship feeding; "choking" (swollen neck held in "S," breast pointed at ground). Male head tosses, neck stretches, calls. NEST: Of grass, moss, debris, lined with fine grass, feathers; oft concealed under veg. Perennial site, constantly rebuilt. EGGS: Olive/light-blue/cinnamon, marked with brown. 2.9" (72 mm). DIET: Scavenger, eats anything from garbage to berries; opportunistic predator on adult birds, eggs and young of other gulls. CONSERVATION: Winters s (mostly pelagic and along coasts) through West Indies and C.A. Increased numbers and expanding range due to reduced egg predation by humans and increased availability of garbage to supplement diets. NOTES: Colonial, usu near water. Occ polygyny and female-female "pairings" reported in Great Lakes. Young solicit feeding by bowing to adult, and touching or holding adult's bill. Both sexes brood. Young form crèches; fed for up to 40 days postfledging (very long for gull). Esp strong site tenacity. Competes with Great Black-backed Gull for best nesting habitat. Frequent pirate. Adult plumage attained in fourth year. STANFORD. NOTES: ESSAYS: Feeding Birds; Eye Color; Crèches; Empty Shells; Gulls and Predators; Parent-Chick Recognition; Site Tenacity. REFERENCES: Burger, 1983, 1984; Cramp and Simmons, 1983; Morris and Haynes, 1977.