Ring-necked Duck

Aythya collaris
STANFORD LOCATIONS:

Uncommon winter visitor in more open, deeper water at Lagunita, occasionally in small flocks.
  
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.
ESSAYS: Bird Communities; Dabblers vs. Divers; Metallic Poisons; Feathered Nests; Color of Eggs.
REFERENCES: Bellrose, 1976; Gooders and Boyer, 1986; Hohman, 1985, 1986.

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Except for Stanford Locations, the material in this species treatment is taken, with permission, from The Birder's Handbook (Paul Ehrlich, David Dobkin, & Darryl Wheye, Simon & Schuster, NY. 1988).