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Donald H. White

Publications and source records attributed to Donald H. White.

65 records · Page 4Linked to original sources

Differential use of fresh water environments by wintering waterfowl of coastal Texas

A comparative study of the environmental relationships among 14 species of wintering waterfowl was conducted at the Welder Wildlife Foundation, San Patricia County, near Sinton, Texas during the fall and early winter of 1973. Measurements of 20 environmental factors (social, vegetational, physical, and chemical) were subjected to multivariate statistical methods to determine certain niche characteristics and environmental relationships of waterfowl wintering in the aquatic community.....Each waterfowl species occupied a unique realized niche by responding to distinct combinations of environmental factors identified by principal component analysis. One percent confidence ellipses circumscribing the mean scores plotted for the first and second principal components gave an indication of relative niche width for each species. The waterfowl environments were significantly different interspecifically and water depth at feeding site and % emergent vegetation were most important in the separation. This was shown by subjecting the transformed data to multivariate analysis of variance with an associated step-down procedure. The species were distributed along a community cline extending from shallow water with abundant emergent vegetation to open deep water with little emergent vegetation of any kind. Four waterfowl subgroups were significantly separated along the cline, as indicated by one-way analysis of variance with Duncan?s multiple range test. Clumping of the bird species toward the middle of the available habitat hyperspace was shown in a plot of the principal component scores for the random samples and individual species.....Naturally occurring relationships among waterfowl were clarified using principal comcomponent analysis and related multivariate procedures. These techniques may prove useful in wetland management for particular groups of waterfowl based on habitat preferences.

The Wilson Bulletin↗

Waterfowl exposure to lead and steel shot on selected hunting areas

Gizzards and wingbones from immature mallards ( Anas platyrhynchos ), pintails ( Anas acuta ), black ducks ( A. rubripes ), and Canada geese ( Branta canadensis ) were collected from 12 national and stat hunting are.as during the hunting season of 1974-75. The gizzards were examined for the occurrence of lead and steel shot and the wingbones were analyzed for lead residues. Incidence of lead shot in gizzards ranged from 1.3 percent in mallards from Monte Vista National Wildlife Refuge to 29 percent in pintails from Sauvie Island Wildlife Management Area. Lead in wingbones ranged from trace residues (<0.5 ppm) to 345 ppm. The incidence of steel shot in gizzards surpassed lead shot on some refuges that have had mandatory steel shot programs. There was a significant correlation between frequency of lead shot in gizzards and lead residues in wingbones.

Journal of Wildlife Management↗

Residues of environmental pollutants and shell thinning in merganser eggs

Clutches of merganser eggs were collected in 1973 and 1975 to determine whether levels of organochlorines and mercury might be responsible for possible population declines and to compare eggshell measurements with those of early museum collections. One egg per clutch was selected randomly for chemical analysis. Overall, residues of DDE, PCB?s, and mercury were low in Hooded Merganser eggs; locality means for DDE ranged from 0.07 to 13.2 ppm, PCB means ranged from 0.44 to 4.91 ppm, and mercury means ranged from 0.16 to 1.49 ppm on a wet-weight basis. Residues of DDE and PCB?s appeared to be high in Red-breasted and Common merganser eggs. DDE averaged 15.7 ppm in Red-breasted Merganser eggs and PCB?s averaged 44.6 ppm; Common Merganser eggs contained an overall mean of 19.5 ppm DDE and 61.0 ppm PCB?s. Hooded Merganser eggs from the Midwest had thinned 8.3%, but the change was not significant. Highly significant shell thinning was detected in Red-breasted and Common merganser eggs; Red-breasted Merganser eggs were 17.7% thinner and those of Common Mergansers were 23.5% thinner than museum collections.

The Wilson Bulletin↗

Nationwide residues of mercury, lead, cadmium, arsenic, and selenium in starlings, 1973

Starlings ( Sturnus vulgaris ) collected in 1973 at 51 sites throughout the continental United States were analyzed for mercury, lead, cadmium, arsenic, and selenium. All samples contained detectable levels of these elements. In general, residues were low: mercury residues ranged from <0.01 to 0.20 ppm: lead, from <0.10 10 3.20 ppm: cadmium, from <0.05 to 0.20 ppm: arsenic, from <0.05 to 1.40 ppm: and selenium, from 0.10 to 1.10 ppm. There was a significant overall decline in mercury and lead residues in starlings since 1971, and a significant increase in arsenic residues. Lead residues were significantly higher in starlings from urban areas than from rural areas.

Pesticides Monitoring Journal↗

Chemical pollutants in field-collected canvasback tissues, eggs, and food materials

In 1972 studies began on the levels of environmental pollutants in canvasback tissues, eggs, and food items. The purpose of the studies were to determine if the levels of toxic chemicals found in canvasbacks were of the magnitude to cause problems affecting reproduction and survival. Overall, levels of organochlorine pesticides and PCB's were low in canvasbacks and their eggs. Some individual birds, however, laid eggs with elevated residues of DDE (12.1 ppm) or PCB's (28.6 ppm). There was no significant difference between eggshell thicknesses of 1972-73 and pre-1946 collections. About 12% of the canvasbacks analyzed had elevated levels of blood lead with reduced ALAD enzyme activity. Adult canvasbacks collected from the Chesapeake Bay in 1975 had moderate to high levels of cadmium in their kidneys. Cadmium, in excessive amounts is very toxic and can curtail spermatogenesis in male birds. Although no single toxic chemical found in wild canvasbacks appears to be a major factor in population declines, the cumulative effects of sublethal levels of all the pollutants may render birds susceptible to disease, hunting pressure or predation.

Book chapter↗

Residues of organochlorines and heavy metals in ruddy ducks from the Delaware River, 1973

In December 1973, eight ruddy ducks killed in an oil spill on the Delaware River were collected to be analyzed for residues of environmental pollutants. Whole carcasses were analyzed for organochlorine pesticides and livers were examined for lead, cadmium, and mercury. Residues of polychlorinated biphenyls and DDT and/or its metabolites were present in all carcasses. Dieldrin and hexachlorobenzene were present in seven of the eight samples. All livers contained detectable levels of lead, cadmium, and mercury.

Pesticides Monitoring Journal↗

Nationwide residues of organochlorines in wings of adult mallards and black ducks, 1972-73

Organochlorine residues in wings of adult mallards and black ducks were monitored during the 1972-73 hunting season. DDE, DDT, DDD, dieldrin, and polychlorinated biphenyls (PCB's) were present in all samples. Mallard wings from Alabama contained the highest mean levels of DDE, DDT, DDD, dieldrin, and PCB's. Mallards and black ducks from the Atlantic Flyway and mallards from the Pacific Flyway contained significantly lower DDE residues than in 1969-70. Black ducks from the Atlantic Flyway contained significantly less dieldrin than in 1969-70, and mallards in the Central and Pacific Flyways contained significantly lower levels of PCB's. As in 1969-70, DDE residues were lowest in the Central Flyway and highest in the Atlantic Flyway. The average PCB level remained unchanged in the Atlantic Flyway but was higher in the Mississippi Flyway than in 1969-70, probably because of the unusually high levels in Alabama samples. All organochlorine residues in black ducks from the Atlantic Flyway significantly correlated. DDE concentrations in mallards from the Atlantic Flyway significantly correlated with those of DDT, DDD, and PCB's.

Pesticides Monitoring Journal↗

Nationwide residues of organochlorines in starlings, 1974

Organochlorine residues in starlings (Sturnus vulgaris) from 126 collection sites were monitored during the fall of 1974. DDE, DDT, polychlorinated biphenyls (PCB's), and benzene hexachloride were present in all samples. Dieldrin, heptachlor expoxide, hexachlorobenzene, and oxychlordane were present in approximately 97% of the samples. DDE, dieldrin, and PCB residues in starlings were significantly lower than they had been in 1972.

Pesticides Monitoring Journal↗

Impacts of chemicals on waterfowl reproduction and survival

Residues of organochlorine pesticides, PCB's, heavy metals, and other toxic chemicals are ubiquitous in the biosphere and are commonly found in tissues and eggs of wild birds. This paper reviews research on the effects of these chemicals, with particular reference to waterfowl. Extensive mortality of waterfowl has occurred in the Gulf Coast region as a result of ingestion of aldrin-treated rice seed. Populations of fulvous tree ducks (Dendrocygna bicolor) have declined in recent years in that area. DDE impaired reproduction of both mallards (Anas platyrhynchos) and black ducks (Arias rubripes) in experimental studies, resulting in thin shells, cracked eggs, and poor hatching success. Eggs incubated by the hens broke and cracked more frequently than those in incubators. In the field, residues are higher in ducks that feed on animal material than in vegetarians; differences are pronounced both geographically and among species. Mercury at levels that occur in certain heavily polluted areas in the United States and Canada has, in experimental studies, lowered the reproductive success of mallards and black ducks and reduced the survival of ducklings. Oil spills have killed many waterfowl as a result of oiled feathers and the intake of oil and more indirect physiological effects have been shown experimentally. Pollutants may affect waterfowl indirectly by changing the habitat and directly as a result of intake of toxic substances. They are unlikely to have been directly limiting factors in populations of such species as mallards. Their involvement with problem of other species, including canvasbacks (Aythya valisineria) and mergansers has still to be explored.

International Waterfowl Symposium↗