Thesis (M.S.)--University of Montana, 2008. / Title from title screen. Description based on contents viewed Aug. 13, 2008. Includes bibliographical references (p. vi-xiv).

Thesis (Ph. D.)--Illinois State University, 1983. / Title from title page screen, viewed May 3, 2005. Dissertation Committee: Robert Weigel (chair), John Cralley, Dale Birkenholz, Edward Mockford, Alan Katz. Includes bibliographical references (leaves 208-214) and abstract. Also available in print.

The Fraser delta tidal marshes are important for migrating and wintering ducks, in particular, Mallard, Pintail, Widgeon, and Green-winged Teal. Agricultural, residential, and industrial development threaten the tidal marshes with destruction and quality loss. In order to preserve and protect the most valuable areas, and perhaps improve the characteristics which attract ducks, it was considered necessary to determine areas of most value, and the environmental characteristics which could be improved. A study of the occurrence and food habits of ducks on the tidal marshes was considered to be the best means of determining the importance of each unit. The relative importance of the tidal marshes for loafing and feeding habitat was indicated from a synthesis of all available information on duck use of the entire delta area. Aerial censuses conducted throughout two winters provided data on the distribution and abundance of Mallard, Pintail, Widgeon, and Green-winged Teal on the foreshore and adjacent upland. It was found that an annually variable population of ducks was present from September until May, with the largest numbers occurring during fall and spring migrations. The tidal marshes attracted approximately one-half the ducks on the deltas— with the largest proportions occurring in September, early October, late March, April, and May.. All four census units of the tidal marsh attracted similar winter totals of ducks although the relative number at each unit varied throughout the winter. As all of the tidal marshes appeared important to ducks, the features of all of them were studied. Area was determined from aerial photographs, and topographical relationships were determined from known tide levels. Composition and distribution of vegetation was determined from line transects. Relative production of seeds was determined from line transects and seed samples. The tidal marshes were found to cover approximately 3,733 acres, sloping from the approximately thirteen foot to the seven foot tide level. A six to eighteen inch "drop-off", which usually occurred near the ten foot tide level, separated the tidal marsh into an upper and lower zone, each with a different vegetative composition. Fourteen plant species were found, of which five Cyperaceae species, Scirpus americanus , Carex lyngbyei , Eleocharis macrostachya , Scirpus paludosus , and Scirpus validus composed ninety-three percent of all plants. The first two species, dominant on the lower and upper zones respectively, formed seventy percent of all plants. Distribution appears to be determined by the degree of tidal flooding, the degree of local drainage, and possibly by undemonstrated differences in soil and water salinity. Seed production varied annually, and was related to the degree of tidal flooding. Scirpus validus and Carex Lyngbyei produced the most seeds, followed next by Scirpus americanus. Ducks were collected on the tidal marshes and adjacent agricultural areas. Analysis of their stomach contents revealed that Carex Lyngbyei, Scirpus validus and Scirpus americanus were the most important- tidal marsh food items. Polygonum lapathifolium and P. persicaria were the most important seed foods taken on the agricultural areas. Although Mallard, Pintail, and Green-winged Teal consumed mostly seeds, Widgeon consumed primarily green vegetation, including winter rye, Lolium sp., and several Gramineae species. A synthesis of the available information indicates that the tidal marshes were most important as loafing areas from October until January, while during the remainder of the period, from September until May, they were also important for the provision of food. The control of water levels, by diking and pumping, appears to be essential for the improvement and protection of the tidal marshes. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--University of Wisconsin--Madison, 1951. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 188-192).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1942. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [i]-ii).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1938. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves i-ii).

Thesis (Ph.D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (587-624).

Cyathocotyle bushiensis (Digenea) and Sphaeridiotrema globulus (Digenea) are gastrointestinal pathogens of waterfowl, and are known to co-occur in salvaged ducks. The intensity and time-dependent pathogenesis induced by single infections of the two digeneans, and concurrent infections were studied in two species of dabbling ducks. Gross tissue pathology by single C. bushiensis infection was found to be a function of both the intensity and the duration of infection. Infection with single species infections of C. bushiensis and S. globulus was associated with decreased weight gain, tendencies for increased body temperatures and increased hematological parameters in Pekin ducklings. The hematological parameters in blue winged teal infected with C. bushiensis were found to decrease. Infection with S. globulus did not induce any significant systemic changes in the blue winged teal. A preliminary study of the effects of concurrent infection on the duck hosts suggests that in general, concurrent infection enhances the detrimental aspects of single infection, decreasing weight gain, increasing body temperatures, and decreasing hematological parameters in both species.

No description available.

No description available.