Publications

No abstract available.

During the period 2-4 April 1981 about 100 birds, mostly ducks and geese, were found dead and dying in a rice field near Sweet Lake, Calcasieu Parish, Louisiana. Fresh specimens were collected to determine the cause of mortality. Birds were placed individually in polyethylene freezer bags, tagged, and frozen soon after collection. Four snow geese (Chen caerulescens), two blue-winged teal...

The relationship between pack size and two parameters of reproductive success (litter size at 7–8 months and pup weights at 5–6 months) were determined for two wolf (Canis lupus) populations in northern Minnesota. Pup weights were not correlated with pack size for either population. Litter size, however, was correlated with pack size, but the direction of the relationship varied between...

No abstract available.

Dramatic changes in the food habits and distribution of Chesapeake Bay canvasbacks (Aythya valisineria) generated a desire to better understand the energetics and behavior of this species on its wintering grounds. Captive canvasbacks were maintained ad libitum on 5 diets during the winters of 1978-80 to evaluate varying protein and energy levels in the diets. Food consumption, weight...

Two wild California Condors contained moderate to high levels of DDE in their tissues. The levels found could be high enough to cause reproductive problems in adult condors, if the assumption is made that condors are as susceptible to DDE as many other species of birds of prey. Other organochlorines occurred at low levels and probably were not high enough to cause deleterious effects...

No abstract available.

Se ofrece un nuevo metodo para computar las oscilaciones demograficas de las aves a lo largo de los anos. Con los datos suministrados por el proyecto 'Aves nidificantes en Norteamerica' , se indican en la Tabla 1 las pautas de cambio numerico de una serie seleccionada de aves holarticas.

No abstract available.

We examined the problem of heterogeneous survival and recovery rates in bird banding estimation models. We suggest that positively correlated subgroup survival and recovery probabilities may result from winter banding operations and that this situation will produce positively biased survival rate estimates. The magnitude of the survival estimate bias depends on the proportion of the...

Behavioral and physiological responses of common grackles to dietary concentrations of dicrotophos, fenitrothion, fenthion, and methyl parathion suggest mortality was largely due to pesticide-induced anorexia. Mortality was dose related, though consumption of treated diets was reduced such that birds on different geometrically arranged concentrations of the same pesticide ingested about...

Gray wolves (Canis lupus) were studied from April-1972 through April 1974 in the Superior National Forest in northeastern Minnesota by radio-tracking and simulated howling. Based on replies during 217 of 456 howling sessions, the following recommendations were derived for using simulated howling as a census technique: (1) the best times of day are dusk and night; (2) July, August, and...