Gadwall Anas strepera Linnaeus       Field Guide IDs: NG-78; G-48; PE48; PW-pl 14; AE-pl 135; AW-pl 125; AM (I)-168 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F I: 24-27 DAYS PRECOCIAL 2 F 8-11 (5-13) MONOG F: 48-56+ DAYS F INSECTS AQUATIC .....INVERTS SURFACE .....DIVES BREEDING: Freshwater (and rarely brackish) marshes, brushy, grassy areas away from water; on lake islands. 1 brood. DISPLAYS: In courtship, male raises black posterior out of water and shows speculum while bobbing head. See: Duck_Displays. NEST: Usu concealed in dense grass, tall reeds, or under brush; made of nearby veg. Building continues during laying. Lined with finer materials; down added during incubation. EGGS: White. 2.2" (55 mm). DIET: Grass, aquatic plants, nuts, grain; aquatic invertebrates, small vertebrates. Dives for food more than most dabblers. In winter, mostly aquatic veg, algae. CONSERVATION: Winters s to s Mexico. Range expanding e. NOTES: Nesting success often higher than other dabblers. Strong female nest site tenacity. Nest parasitism by other Gadwalls and by scaup, not uncommon. Breeding season later than most other ducks. Gadwalls feed farther from shore than do other dabblers. STANFORD. NOTES: Uncommon to fairly common winter visitor at Lagunita, usually seen foraging in shallows at the edge of the lake. Birds lingering into spring may occasionally nest here, although breeding has not yet been recorded. ESSAYS: Dabblers vs. Divers; Piracy; Parasitized Ducks; Site Tenacity. REFERENCES: Bellrose, 1976; Gooders and Boyer, 1986; Hepp, 1985; Hines and Mitchell, 1983, 1984.