Publications

Mixed conifer and hardwood stands in southwestern Oregon were studied to explore the hypothesis that competition effects on individual-tree growth and survival will differ according to the species comprising the competition measure. Likewise, it was hypothesized that competition measures should extrapolate best if crown-based surrogates are given preference over diameter-based (basal...

We compared habitat use, forage characteristics, and group size among preparturient, parturient, and nonparturient female caribou (Rangifer tarandus) during and after the birthing season to test hypotheses involving acquisition of forage and risk of predation. We monitored 39 radiocollared females from the Mentasta caribou herd, Alaska, in 1994 and 40 animals in 1995. Group size of...

Genetic and morphological diversity of Phyllodoce empetriformis (Sw.) D. Don and Phyllodoce glanduliflora (hook.) Cov. were surveyed in Mount Rainier National Park in the Cascade Mountains of Washington State. Paired populations at high and low elevations were sampled at three study areas between 1720- and 2451-m elevation. Allozyme analysis of four polymorphic loci indicates high levels...

Improved understanding of tree growth responses to climate is needed to model and predict forest ecosystem responses to current and future climatic variability. We used dendroecological methods to study the effects of climatic variability on radial growth of a subalpine conifer, mountain hemlock (Tsuga mertensiana). Tree-ring chronologies were developed for 31 sites, spanning the...

Effects of color bands on adult birds have been investigated in many studies, but much less is known about the effects of bands on birds banded at hatch. We captured Semipalmated Sandpiper (Calidris pusilla) chicks at hatch on the Alaskan North Slope and attached 0–3 bands to them. The chicks were resighted and reweighed during the subsequent two weeks. The number of chicks banded varied...

Humans have affected grizzly bears (Ursus arctos horribilis) by direct mortality, competition for space and resources, and introduction of exotic species. Exotic organisms that have affected grizzly bears in the Greater Yellowstone Area include common dandelion (Taraxacum officinale), nonnative clovers (Trifolium spp.), domesticated livestock, bovine brucellosis (Brucella abortus), lake...

Cover condition and its influence on nesting success, survival, and body condition of ring-necked pheasants (Phasianus colchicus) were evaluated at Tule Lake National Wildlife Refuge (TLNWR) and Lower Klamath National Wildlife Refuge (LKNWR). Inadequate nesting cover was responsible for extremely low nest success early in the nesting season at TLNWR. Later in the season at TLNWR, spring...

We investigated the influence of military training on the abundance and behavior of raptors at a military training area in the Snake River Birds of Prey National Conservation Area in Idaho during the breeding seasons of 1991a??1994. Raptor counts on military training ranges did not differ when we compared all training days to all non-training days. However, during one period of intensive...

No abstract available.

A sensitive resettable odometer reading to 0.01 mile facilitated censusing breeding male redwinged blackbirds (Agelaius phoeniceus) from a vehicle. Territorial males along roadsides were 'marked' with recorded mileage readings rather than with landmarks of the types employed by Hewitt for censuses based on the Lincoln index principle. Sensitive odometers that can be reset have many...

Locomotion of nematodes in soil is important for both practical and theoretical reasons. We constructed a model for rate of locomotion. The first model component is a simple simulation of nematode movement among finite cells by both random and directed behaviours. Optimisation procedures were used to fit the simulation output to data from published experiments on movement along columns...

Electrocution on power lines is one of many human-caused mortality factors that affect raptors. Cost-effective and relatively simple raptor-safe standards for power line modification and construction have been available for over 25 years. During the 1970s and early 1980s, electric industry efforts to reduce raptor electrocutions were very coordinated and proactive, but predictions about...