Ruddy Duck

Oxyura jamaicensis
STANFORD LOCATIONS:

Uncommon winter visitor in more open, deeper water at Lagunita.
  
Nest
Location
Nest
Type
Eggs
Mating System
Dev.
Parental Care
Primary &
2ndary Diet
Foraging
Strategy
F
I: 23-26 DAYS
PRECOCIAL 2
 
F
6-8
(6-10)
MONOG
F: 42-48 DAYS
F
GREENS
BREEDING: Usu densely vegetated freshwater marsh, occ lake, pond. 1 brood, 2 in s.
DISPLAYS: "Bubbling" by male used both in courtship and aggression toward other males. See: Duck Displays.
NEST: In tall emergent veg, built of same. Lined sparsely with finer materials. Occ uses abandoned coot or Redhead nest.
EGGS: Creamy white, nest-stained. 2.5" (62 mm).
DIET: Mostly aquatic insect larvae, also aquatic snails, other invertebrates; aquatic veg, esp in winter. Most food obtained by straining animals from soft substrate ooze.
CONSERVATION: Winters s to n C.A. and Bahamas.
NOTES: Brood parasite, often laying eggs in nests of other ducks, esp Redhead, Canvasback, also grebes, rails. Parasitism rate not necessarily related to environmental conditions; parasitism higher among Ruddies than between Ruddies and other species. Male deserts prior to or early in incubation; males often seen accompanying females with broods, but these males are not the broods' parents, apparently simply males attracted to females. Young soon capable of diving effectively but helpless on land.
ESSAYS: Parasitized Ducks; Dabblers vs. Divers; American Coots; Brood Parasitism; Parental Care; Monogamy.
REFERENCES: Bellrose, 1976; Gooders and Boyer, 1986; Joyner, 1977, 1983; Siegfried, 1976.

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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).