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Publications

Filter Total Items: 1990

Fire and aquatic ecosystems in forested biomes of North America

Synthesis of the literature suggests that physical, chemical, and biological elements of a watershed interact with long-term climate to influence fire regime, and that these factors, in concordance with the postfire vegetation mosaic, combine with local-scale weather to govern the trajectory and magnitude of change following a fire event. Perturbation associated with hydrological processes is prob
Authors
Robert E. Gresswell

Variation in age at metamorphosis across a latitudinal gradient for the tailed frog, Ascaphus truei

Tailed frogs (Ascaphus truei) occur in permanent, cold streams in northwestern North America. Their tadpoles reportedly undergo metamorphosis after 2-4 years. Coastal populations that we examined transformed in 2 yr from the Olympic peninsula in Washington to northern Oregon, but in 1 yr from central Oregon to northern California. One inland site in northern California had a 2-yr period. Age at me
Authors
R. Bruce Bury, M. J. Adams

Effects of sample size on KERNEL home range estimates

Kernel methods for estimating home range are being used increasingly in wildlife research, but the effect of sample size on their accuracy is not known. We used computer simulations of 10-200 points/home range and compared accuracy of home range estimates produced by fixed and adaptive kernels with the reference (REF) and least-squares cross-validation (LSCV) methods for determining the amount of
Authors
D.E. Seaman, J.J. Millspaugh, Brian J. Kernohan, Gary C. Brundige, Kenneth J. Raedeke, Robert A. Gitzen

DDE, PCBs, cadmium, lead, and mercury concentrations in rhinoceros auklets from Washington

In July 1981, 5 adult rhinoceros auklets (Cerorhinca monocerata) were captured on the ground near nesting areas on each of Protection and Destruction Islands, Washington. The birds were euthanized, and their livers and kidneys removed and analyzed. Levels (I?g / g wet weight) of DDE (0.11 to 0.95), polychlorinated biphenyls (no residue detected [ND] to 1.1), mercury (0.60 to 1.8), and lead (ND to
Authors
L. J. Blus, R. E. Fitzner, L.L. Leschner, U.W. Wilson

Bat activity in thinned, unthinned, and old-growth forests in western Oregon

Many aspects of the influences of forest management activities on bats (Chiroptera) in the Pacific Northwest are poorly known. We compared thinned and unthinned forest stands of the same age and old-growth forest stands to determine potential differences in structure and amount of use by bats. We hypothesized that activity levels of bats would differ in stands differing in structure as a result of
Authors
Marcia L. Humes, J. P. Hayes, Michael W. Collopy

Creating raptor benefits from powerline problems

Powerlines benefit raptors by providing enhanced nesting and roosting sites. However, they also can kill raptors by electrocution and raptors can interfere with power transmission. The electrocution problem has been reduced by correcting existing lethal lines and implementing electrocution safe designs for new lines. Remedial actions include pole modifications, perch management and insulation of
Authors
Michael N. Kochert, R.R. Olendorff

Effects of military training activities on shrub-steppe raptors in southwestern Idaho, USA

), northern harriers (Circus cyaneus), burrowing owls (Athene cunicularia), and short-eared owls (Asio flammeus) inside and outside a military training site in the Snake River Birds of Prey National Conservation Area, southwestern Idaho. The Orchard Training Area is used primarily for armored vehicle training and artillery firing by the Idaho Army National Guard. Relative abundance of nesting pair
Authors
Robert N. Lehman, Karen Steenhof, Michael N. Kochert, L.B. Carpenter

Water-use patterns of woody species in pineland and hammock communities of South Florida

Rockland pine forests of south Florida dominated by Pinus elliottii var. densa characteristically have poor soil development in relation to neighboring hardwood hammocks. This has led to the hypothesis that Everglades hammock trees are more reliant on soil moisture derived from local precipitation whereas pineland plants must depend more on groundwater linked to broader regional hydrologic pattern
Authors
Sharon M. Ewe, Leonel S. Sternberg, David E. Busch

Long-term prairie falcon population changes in relation to prey abundance, weather, land uses, and habitat conditions

We studied a nesting population of Prairie Falcons (Falco mexicanus) in the Snake River Birds of Prey National Conservation Area (NCA) from 1974-1997 to identify factors that influence abundance and reproduction. Our sampling period included two major droughts and associated crashes in Townsend's ground squirrel (Spermophilus townsendii) populations. The number of Prairie Falcon pairs found on lon
Authors
Karen Steenhof, Michael N. Kochert, L.B. Carpenter, Robert N. Lehman

Reproductive characteristics of migratory golden eagles in Denali National Park, Alaska

We describe reproductive characteristics of Golden Eagles (Aquila chrysaetos) breeding in Denali National Park, Alaska during an entire snowshoe hare (Lepus americanus) cycle, 1988-1997. Data on nesting eagles were collected at 58 to 72 nesting areas annually using two aerial surveys. Surveys were conducted during the incubation period to determine occupancy and nesting activities and late in the
Authors
Carol L. McIntyre, Layne G. Adams