Publications

The Woodworth Study Area (WSA) was purchased by the U.S. Fish and Wildlife Service (FWS) during the early 1960's as a waterfowl production area. Unlike most such areas, its primary purpose was not to provide waterfowl breeding habitat directly, but instead it was dedicated for use as a research area to develop information for better management of upland and wetland habitats. This article

We developed an ELISA procedure to assess the presence of M. Anatis-specific serum antibody in ducks. Sera from exposed and unexposed Pekin ducks (Anas platyrhynchos) were used to standardize tile ELISA and to establish reference ranges to classify ELISA results as exposed or not exposed. We conducted serological surveys of female waterfowl in the central and eastern United States...

No abstract available.

Grasslands and wetlands of the northern prairies provide important breeding habitat for a number of birds. Deciding which species deserve most attention in managing those habitats depends, in part, on the importance of the area to the species. Many species in northern prairies are more common elsewhere and need no special consideration in that area. Several species, however, are...

Features that determine the composition of avian communities have received extensive and enthusiastic attention, both empirically and theoretically (e.g., Cody 1974; Strong et al. 1984; Wiens, 1989a,b). Interspecific competition for limited resources is one influence widely regarded as critical, but others include species-specific responses to environmental conditions, predation...

Zebra mussels (Dreissena polymorpha) invaded the Great Lakes in the mid-1980s and quickly reached high densities. The objective of this study was to determine current consumption of zebra mussels by waterfowl in the Great Lakes region. Feeding Lesser Scaups (Aythya affinis), Greater Scaups (A. marila), Canvasbacks (A. valisineria), Redheads (A. americana), Buffleheads (Bucephala albeola)...

Duckling survival, an important factor affecting annual recruitment, has not been determined adequately for canvasbacks (Aythya valisineria). We investigated the magnitude, timing, and causes of mortality of canvasback ducklings from hatch to fledging at the Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota during 1987-90. During the 4 years, 217 day-old ducklings were...

We examined the trophic roles of two nonindigenous species, ruffe (Gymnocephalus cernuus) and white perch (Morone americana), in the food web of a western Lake Superior coastal wetland, using stable isotope techniques. The δ15N signature of ruffe was similar to published values for YOY yellow perch (Perca flavescens), and intermediate to those of white sucker (Catostomus commersoni), a...

A project to produce a comprehensive, site-specific butterfly list that could serve as a basis for future monitoring of butterfly populations and as an aid in making management decisions for the area.

Significant correlations were found among the annual growth increments of stream fish, trees, and climate variables in the Ozark region of the United States. The variation in annual growth increments of rock bass (Ambloplites rupestris) from the Jacks Fork River was significantly correlated over 22 years with the ring width of four tree species: white oak (Quercus alba), post oak...

A major part of the midcontinent greater white-fronted goose (Anser albifrons) population stages for several weeks in spring in the Rainwater Basin Area (RBA) of south-central Nebraska where substantial mortality from disease occurs periodically. Effective management of this population requires better data on use of habitat, vulnerability to disease, and the role of staging areas in...

We measured the variation of some commonly used fish community attributes for two warmwater stream reaches during June–October 1992 and 1993. Habitat‐specific variation among samples, expressed as coefficients of variation (SD/mean) collected throughout the study ranged from 0.13 to 1.58 and were lower for community‐level attributes such as species richness (total number of species) and...