Ring-necked Duck Aythya collaris Donovan       Field Guide IDs: NG-86; G-54; PE-58; PW-pl 11; AE-pl 121; AW-pl 90; AM(I)-176 Nest Location Nest Type Eggs & Mating System Dev. & Parental Care Primary & 2ndary Diet.. Foraging Strategy F I: 26-27(25-29) DAYS PRECOCIAL 2 FLOATING F 8-10 (6-14) MONOG F: 49-56 DAYS F AQUATIC .....INVERTS BREEDING: Freshwater marsh, slough, bog, wooded lake, swamp, rarely saline habitats. 1 brood. DISPLAYS: See: Duck_Displays. NEST: Dry and semidry sites near water, on hummock, or in clumped bushes at water's edge, occ over shallow water. Building does not precede laying, but begins by 3rd-4th egg. Compact, of bent fine grass, moss, other nearby material. Lined abundantly with down. EGGS: Olive-gray/olive-brown buff. 2.3" (58 mm). Varied, but consistent within clutch. DIET: Proportion of animal food is habitat-dependent. As with most waterfowl, proportion of inverts (esp aquatic insects, snails) increases after arrival on breeding grounds. Young eat mostly inverts, esp for first 2-3 weeks. CONSERVATION: Winters s to West Indies and Panama. Breeding range expanded e in rnid-1900s. Lead shot poisoning not uncommon. NOTES: Male remains with mate through most of incubation, occ to hatching. Pair together when female off nest. In e usu nest in low-productivity wetlands often avoided by other ducks. Young and adult food habits usu more generalized than those of other members of this genus. STANFORD. NOTES: Uncommon winter visitor in more open, deeper water at Lagunita, occasionally in small flocks. ESSAYS: Bird Communities; Dabblers vs. Divers; Metallic Poisons; Feathered Nests; Color of Eggs. REFERENCES: Bellrose, 1976; Gooders and Boyer, 1986; Hohman, 1985, 1986.