Publications

No abstract available.

No abstract available.

During 1985 and 1986 I studied interspecific brood parasitism among seven species of waterfowl nesting on 36 islands and 24 peninsulas in central North Dakota. On islands, 40% of 178 nests were parasitized with an average of 4.3 parasitic eggs, and on peninsulas 2% of 275 nests were parasitized with an average of 2.2 parasitic eggs. Redheads (Aythya americana) were the primary parasite, adding egg

We examined the feeding ecology of Northern Pintails (Anas acuta), Northern Shovelers (A. clypeata), and Ruddy Ducks (Oxyura jamaicensis) wintering on drainwater evaporation ponds in California from 1982 through 1984. Pintails primarily consumed midges (Chironomidae) (39.3%) and widegeongrass (Ruppia maritima) nutlets (34.6%). Shovelers and Ruddy Ducks consumed 92.5% and 90.1% animal matter, respe

No abstract available.

We used diurnal aerial census data to examine habitat use patterns of ducks wintering in the southern San Joaquin Valley, California from 1980-87. We calculated densities (birds/ha) for the northern pintail (Anas acuta), mallard (A. platyrhynchos), green-winged teal (A. crecca), cinnamon teal (A. cyanoptera), shoveler (A. clypeata), ruddy duck (Oxyura jamaicensis), and total ducks in each of 5 hab

Canvasback (Aythya valisineria) broods (n = 69) accompanying marked females were observed during five summers in southwestern Manitoba. We evaluated movements of broods of different age classes ( 14 days old, 15-28 days old, and >28 days old) among ponds of different size and wetland class. Of 202 brood sightings, 7% occurred on seasonal ponds, 81% on semipermanent ponds, and 12% on permanent pond

Habitat use and survival by nine mallard (Anas platyrhynchos) broods from nests on the James River floodplain and adjacent drift plain were monitored during summer 1987. Radio-marked broods were relocated an average of 22% of the time in the river channel, 22% in oxbow ponds, 43% in a large sewage lagoon complex, and 13% in basin wetlands. Four of the six broods hatched on the floodplain stayed pr

We examined standing crops and ecology of aquatic invertebrates in agricultural drainwater evaporation ponds in California from October 1982 to March 1983 and September 1983 to March 1984. Evaporation ponds supported low diversities but high standing crops of aquatic invertebrates. A water boatman (Trichocorixa reticulata) and a midge (Tanypus grodhausi) were the most abundant invertebrates, const

Abstract has not been submitted

We observed reverse mounting behavior in a color-banded population of Groove-billed Anis (Crotophaga sulcirostris) in Costa Rica. Sex was determined with measurements and laparotomies. Reverse mounting appeared nearly identical to mounting by males. Of 27 mountings in which at least one bird was banded, 15 were reverse mountings. Only reverse mountings (11 observations) were observed in the pre-br

No abstract available.