Publications

Dramatic changes in the food habits and distribution of canvasbacks (Aythya valisineria) in Chesapeake Bay during the 1970's generated a need to evaluate the nutritional value of food items and the requirements of this species on its wintering grounds. Groups of captive canvasbacks were maintained ad libitum on 5 diets during the winters of 1978-79 and 1979-80 to evaluate the effects of...

Mass and recapture histories of 6,000 Canvasbacks (Aythya valisineria) banded in upper Chesapeake Bay were used to test two hypotheses: (1) early-winter body mass is associated with the probability of surviving the winter, and (2) early-winter body mass is associated with annual survival probability. Data were analyzed by a binary regression method that treated mass as a continuous...

I used captive young and adult American Black Ducks (Anas rubripes) during October-February 1984-1985 to test whether body weight and age affected time of pair-bond formation. Eighty ducks were marked individually, and 10 ducks (6 males and 4 females, half of each age class) were assigned to each of 8 experimental pens. Ducks in 4 pens received an ad libitum diet of commercial duck food...

Ten organochlorine compounds were identified in pools of black duck (Anas rubripes) and mallard (A. platyrhynchos) wings from the 1981–82 hunting season. Most organochlorine compounds occurred very infrequently. Among those compounds positively identified by mass spectrometry, DDE and, secondarily, PCB had the highest frequencies of occurrence. Other compounds, positively identified and...

The entire banding and recovery record for Atlantic brant (Branta bernicla hrota) was analyzed to determine recovery and survival rates for 1956-75. Composite survival rates for all adults (sex of banded birds was not recorded) during the 19-year period ranged from 0.984 to 0.591 (x = 0.785). Survival rates for Atlantic brant are relatively high among all geese but at the low end of the...

The numbers of host-seeking adult American dog ticks, Dermacentor variabilis (Say), in a sweet gum field in Maryland reflected changes in the population density of a host species, the meadow vole, Microtus pennsylvanicus (Ord), which within 1.5 yr fell from an estimated 157 to 8 voles on a 0.8 ha grid. During high vole density, there was no significant difference (P > 0.05) in tick...

An important topic of waterfowl ecology concerns the relationship between the physiological condition of ducks during the nonbreeding season and fitness, i.e., survival and future reproductive success. We investigated this subject using direct band recovery records of mallards (Anas platyrhynchos) banded in autumn (1 Oct-15 Dec) 1981-83 in the Mississippi Alluvial Valley (MAV) [USA]. A...

Pairs of first-year breeding bobwhites were fed constant or variable concentrations of methamidophos for 15 days, or a control diet in a pair-fed design in which they were matched by body weights to pairs in the constant group. Treatments for the constant group were 5.0, 7.8, 12.3, 19.2, and 30.0 ppm for 5 pairs at each concentration. The number of pairs per concentration and peak...

Over the last decade, data gathered by the U.S. Fish & Wildlife Service's National Contaminant Biomonitoring Program have identified an area of elevated DDE contamination in portions of New Mexico and Texas. Extensive wildlife sampling in 1983 confirmed that DDE, the major metabolite of the insecticide DDT, was present at high concentrations in wildlife at selected sites in the Rio...

Horned larks, Eremophila alpestris (L.), and McCown's longspurs, Calcarius mccownii (Lawrence), were collected at intervals from two winter wheat fields in Montana after aerial application of chlorpyrifos to control cutworms. Both bird species had a high (95–100%) incidence of Lepidoptera, mostly pale western cutworms, Agrotis orthogonia Morrison, in their stomachs at 3 days postspray...

Fenthion, (0,0-Dimethyl0-[3-methyl-4-(methylthio)phenyl] phosphorothioate), a widely used mosquito control agent, has caused wildlife mortality. To simulate a shallow wetland environment, an exposure chamber was used containing water treated with fenthion at 1 and 10 times the field application rate of 112 g active ingredient (AI)/ ha. This system permitted an evaluation of exposure...

No abstract available.