Publications

Radio transmitters are an important tool in waterfowl ecology studies, but little is known about their effects on free-ranging geese. We attached transmitters to female brant (Branta bernicla nigricans) to investigate migration schedules at a fall staging area, return rates to nesting grounds, and nesting rates of returning females in subsequent breeding seasons. Radio-tagged females (n...

No abstract available.

We modified standard aerial survey data collection to obtain the geographic location for each waterfowl observation on surveys in Alaska during 1987-1993. Using transect navigation with CPS (global positioning system), data recording on continuously running tapes, and a computer data input program, we located observations with an average deviation along transects of 214 m. The method...

Black bear damage to 108 lodgepole pine trees was found in mixed conifer habitat in central Oregon. No trees of three other conifer species were injured. Eighty-nine percent of the damage occurred in the same year. Nearly 20% of the freshly damaged trees had bark removed from more than 75% of the circumference and, judging from the fate of trees damaged in prior years, probably

We mounted a video camcorder in a single-engine aircraft to estimate nesting density along 10-m wide strip transects in black brant colonies on the Yukon Delta National Wildlife Refuge, Alaska during 1990-1992. A global positioning system (GPS) receiver was connected to the video recorder and a laptop computer to locate transects and annotate video tape with time and latitude

Survival of young is an important and poorly understood component of waterfowl productivity. We estimated survival of black brant (Branta bernicla nigricans) goslings during summers 1987-89 on the Yukon-Kuskokwim Delta, Alaska, to determine timing and magnitude of gosling mortality and to compare methods of estimating gosling survival. Eighty-two percent of radio-tagged adult females (n...

Alloparental care in birds generally involves nonbreeding adults that help at nests or breeding adults that help raise young in communal nests. A less often reported form involves the amalgamation of broods, where one or more adults care for young that are not their own. We observed this phenomenon among Bristle-thighed Curlew Numenius tahitiensis broods in western Alaska during 1990...

We studied relationships between body size of female Black Brant goslings (Branta bernicla nigricans) late in their growth period and first year survival, eventual adult body size, breeding propensity, and size and volume of clutches they eventually produced to examine the relationship between growth and fitness in this population. We indexed body size by calculating PC1 scores based on...

We measured apparent metabolizability of organic matter, gross energy, nitrogen and cell wall constituents of pelleted alfalfa by Lesser Snow Geese (Chen caerulescens caerulescens. We also used simultaneous measurements of energy expenditure and apparent metabolizable energy intake to estimate heat increment of feeding and net energy for production and maintenance. Apparent...

Population estimates of Spectacled Eiders (Somateria fischeri) on the Yukon-Kuskokwim Delta (YKD), Alaska, suggest that by 1992 the number of birds on this major nesting area had declined to 1,721 pairs, 4% of that estimated in the 1970s (Stehn st al 1993). Consequently, Spectacled Eiders were listed as threatened under the Endangered Species Act. As nesting habitats for this species are...

The Texas coast has experienced considerable urban, industrial, and agricultural growth during the 20th Century. The region provides important wintering habitat to many avian species, including lesser snow geese Chen caerulescens caerulescens. This paper draws the biological and ecological fields into an historical perspective by examining available literature on the development of the...

Information on the size, distribution, and productivity of the California sea otter population is broadly relevant to two federally mandated goals: removing the population’s listing as threatened under the Endangered Species Act (ESA) and obtaining an “optimal sustainable population” under the Marine Mammal Protection Act. Except for the population in central California, sea otters...