Publications

No abstract available.

No abstract available.

Maps generated from bird survey data are used for a variety of scientific purposes, but little is known about their bias and precision. We review methods for preparing maps from point count data and appropriate sampling methods for maps based on point counts. Maps based on point counts can be affected by bias associated with incomplete counts, primarily due to changes in proportion...

Management of gray wolves (Canis lupus) and their prey in interior Alaska has been controversial for three decades (Harbo and Dean 1983). Recently, debate was rekindled with renewed interest in wolf control to bolster two populations of caribou (Rangifer tarandus). Our research in Denali National Park provides insights into the declines in caribou numbers over the last few years that are...

Since the arrival of Columbus in Puerto Rico, the Taino Indian has disappeared and the parrot has just barely survived (Wadsworth 1949; Snyder et al. 1987). The Puerto Rican parrot (Amazona vittata) had shared its habitat with the peaceful Taino Indians for centuries before the arrival of European settlers in the Caribbean.

Colonial waterbirds, that is, seabirds (gulls, terns, cormorants, pelicans) and wading birds (herons, egrets, ibises), have attracted the attention of scientists, conservationists, and the public since the turn of the century when plume hunters nearly drove many species to extinction. The first national wildlife refuge at Pelican Island, Florida, was founded to conserve a large nesting...

Resident sandhill cranes formed a continuous population in Georgia and Florida and widely separated populations along the Gulf Coastal Plain of Texas, Louisiana, Mississippi, and Alabama (Figure). The Mississippi sandhill crane (Grus canadensis pulla) was one of the widely separated populations on the Coastal Plain that bred in pine savannas in southeastern Mississippi, just east of the...

The North American Breeding Bird Survey comprises a network of regularly censussed, road-based survey routes and constitutes the most comprehensive set of data on the relative abundance and population trends of these birds during the summer months. Its value was highlighted in 1989, when the data were used to confirm suspected population declines in a number of species of neotropical...

No abstract available.

The first European Remote Sensing Satellite (ERS-1) synthetic aperture radar (SAR) images offer opportunities for studying glacier surface properties and near-surface features. Analysis of back-scatter values from digital SAR data from 18 January, 7 June, 1 September and 25 October 1993 of Brúarjökull, an outlet glacier on the northeastern margin of the Vatnajökull ice cap, Iceland, that...

Project Summary: The following digital product represents the Acid Deposition Sensitivity of the Southern Appalachian Assessment Area. Areas having various susceptibilities to acid deposition from air pollution are designated on a three tier ranking in the region of the Southern Appalachian Assessment (SAA). The assessment is being conducted by Federal agencies that are members of the...

Streambed-scour was assessed at 1,338 federal-aid bridges in southwestern Indiana during 1991. The assessments were conducted as part of a 7-year study by the U.S. Geological Survey in cooperation with the Indiana Department of Transportation (INDOT) that will evaluate 5,600 bridge sites throughout the State. Measurements and observations of remnant scour made during low-flow discharges...