Publications

Based on the composition of nestling regurgitations collected during 3 breeding seasons, fish were the most important prey group for Great Egrets (Ardea alba: N = 200 nest-day samples; aggregate percent biomass [APB] = 73.4%), Snowy Egrets (Egretta thula: N = 115; APB = 91.4%), and Tricolored Herons (E. tricolor: N = 68; APB = 97.3%). For Little Blue Herons (E. caerulea: N = 57), grass...

Friction threshold velocities (FTVs) were determined for biological soil crusts in different stages of recovery. Particles on the surface of crusts that had been relatively undisturbed for at least 20 years were found to have significantly higher FTVs than those that had been disturbed 5, 10 or 1 years previously (376, 87, and 46 cm sec-1 , respectively). FTV's for crust breakage was...

Road closures frequently are used to manage for Rocky Mountain elk (Cervus elaphus nelsoni), but no studies have evaluated the effects of limited vehicle access on movements and survival of Roosevelt elk (C. elaphus roosevelti). We studied movements and survival of female Roosevelt elk before Road Management Areas (RMA) were designated, and during limited vehicular access from 1991 to...

No abstract available.

Ernpidonax trailIll extirnus is one of several recognized subspecies of the Willow Flycatcher (Unitt 1987, Browning 1993), a neotropical migrant that breeds across much of North America. This southwestern race is a riparian obligate, nesting in dense patches of willow (Salix sp.), willow-cottonwood (Populus sp.), or other similarly structured habitats. In some areas of the Southwest, it...

Whitebark pine seeds Pinus albicaulis are an important food of grizzly Ursus arctos horribilis bears wherever whitebark pine is abundant in the contiguous United States of America; availability of seeds affects the distribution of bears, and the level of conflict between bears and humans. Almost all of the seeds consumed by bears are excavated from middens where red squirrels...

Biotic soil crusts are a worldwide phenomenon in arid and semi-arid landscapes. Metabolic activity of the poikilohydric organisms found in these crusts is dominated by quick and drastic changes in moisture availability and long periods of drought. Under controlled conditions, we studied the role of water content on photosynthetic and respiratory CO2 exchange of three green algal soil...

The pheasant, in its North American range, seems to have had its greatest success in glaciated or in other areas associated with calcareous soils. Success has been slight in areas deficient in calcium.....In Lancaster County, Pennsylvania, no environmental difference other than presence or absence of limestone was discovered that might explain the high population in the limestone valley...

The intestinal helminth fauna of river otters, Lutra canadensis, from the Pacific Northwest was characterized by low species richness and intensity of infection. River otters from the lower Columbia River (n = 23) were infected with 9 species of helminths (83% prevalence); those from a relatively undisturbed reference area near the headwaters of the Trask and Wilson rivers on the Oregon...

We developed a multivariate description of black-tailed jackrabbit (Lepus californicus) habitat associations from Geographical Information Systems (GIS) signatures surrounding known jackrabbit locations in the Snake River Birds of Prey National Conservation Area (NCA), in southwestern Idaho. Habitat associations were determined for characteristics within a 1-km radius (approx home range...

During a mark–recapture study of Townsend's ground squirrels (Spermophilus townsendii) on 20 sites in the Snake River Birds of Prey National Conservation Area, Idaho, in 1991 through 1994, 4407 animals were marked in 17639 capture events. This study of differences in population dynamics of Townsend's ground squirrels among habitats spanned a drought near the extreme of the 130-yr record...

No abstract available.