Ruddy Duck Oxyura jamaicensis Gmelin       Field Guide IDs: NG-96; G-62; P-60; PW-pl 13; AE-pl 111; AW-pl 116; AM (I)-206 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. STANFORD. NOTES: Uncommon winter visitor in more open, deeper water at Lagunita. 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.