The habitat use and energetics of American black ducks (Anas rubripes) wintering at Chincoteague National Wildlife Refuge, Virginia, were investigated. Twenty-two female black ducks were systematically radiotracked on the 25,600 ha study area between 15 December 1985 and 28 February 1986. Diurnal time and energy budgets were constructed by distributing 1,471 scans (collected in 1985-86 and 1986-87) over a time-tide matrix within refuge, saltmarsh, and tidal water habitats. Sixty-four ducks were collected during early, mid, and late winter in 1985-86 to determine changes in carcass composition. The Habitat Suitability Index (HSI) model for wintering black ducks was evaluated. Age affected range and core areas but did not affect habitat selection. Tide, ice, and time of day affected habitat use. Refuge pools were used during the day and saltmarsh was used at night. Subtidal water was used during periods of icing. Black ducks fed least and rested most when in refuge pools but fed most and rested least when in tidal waters. Black ducks curtailed feeding and increased time spent in alert and locomotion behaviors in response to disturbance. Whole carcass analysis indicated that black ducks were at least as fat and heavy in the spring as they were in the fall. Comparisons with similar work in Maine suggested that black ducks wintering in Maine and Virginia expend the same energy at a given temperature. However, because of lower temperatures, black ducks collected at Chincoteague were in relatively better condition than ducks wintering in Maine. / Master of Science

Louisiana’s coastal wetlands support millions of resident and migratory birds annually but account for 80% of the nation’s coastal wetland loss. Marsh terracing is a restoration technique that constructs segmented ridges in open water areas to enhance marsh conditions. Despite widespread use, their value as avian habitat has received limited study. Using ground and aerial surveys, we evaluated avian use of marsh terraces across 24 paired sites (marsh terrace and non-terrace sites) in coastal Louisiana. Avian surveys focused on breeding secretive marsh birds (SMB) and wintering waterfowl. Results indicate that presence or absence of marsh terraces influenced numbers of ducks detected, though relative abundance varied spatially and temporally. The effect on SMB abundance varied by species and environmental variables, including habitat structure and water availability. The study highlights the complexity of bird responses to marsh terracing, emphasizing the importance of considering species-specific habitat preferences and environmental factors in restoration planning.

The goals of this study were to elucidate relationships between food habits and tissue accumulations of heavy metals in Chesapeake Bay waterfowl and to determine effects of chronic cadmium and lead ingestion on energy metabolism in waterfowl. Concentrations of cadmium, lead, copper, and zinc were measured in 774 livers, 266 kidneys, and 271 ulnar bones from 15 species of ducks obtained from the Chesapeake Bay region. Liver and kidney concentrations of cadmium were highest among two carnivorous sea duck species, Clangula hyemalis and Melanitta deglandi. In contrast, lead concentrations in three tissues were generally highest in largely herbivorous species, such as Anas platyrhynchos, Anas rubripes, and Anas strepera. Spent shot may be an important source for tissue burdens of lead in these ducks. No marked trends were observed between food habits and tissue concentrations of copper or zinc. Cadmium and lead concentrations were generally higher in benthic macrophytes than in soft tissues of clams collected from several locations in the Bay. These results suggest that the change that has occurred in the food habits of some Chesapeake Bay ducks, most notably Aythya valisineria to diets composed largely of clams rather than aquatic vegetation probably did not increase ingestion of these elements. In experiments conducted with A. platyrhynchos, chronic ingestion of equal dietary concentrations of cadmium and lead resulted in about 15 times greater accumulation of cadmium than lead in livers and kidneys. However, while ulnar bones accumulated lead, cadmium concentrations in bones remained below detection limits. Cadmium ingestion enhanced renal accumulation of copper and zinc, perhaps due to induction of metallothionein by cadmium. In combination with an imposed food restriction, cadmium ingestion appeared to alter some indices of energy metabolism, such as plasma concentrations of free fatty acids and triiodothyronine, at dietary cadmium levels far below those eliciting similar responses in the absence of a food restriction. Those results suggest the importance of considering interactions with other stressors when examining potential effects of environmental contaminants on wild animals. / Ph. D.

The natural reservoir of influenza A virus (IAV) is wild waterfowl, and all human IAVs have their genetic origins from avian viruses. Neuraminidase inhibitors (NAIs) are currently the best drugs for treatment of human influenza; therefore, the orally available NAI oseltamivir (Tamiflu®) has been stockpiled worldwide as part of pandemic preparedness planning. Re-sistance to NAIs is related to worse clinical outcomes and if a new pandemic influenza virus would be oseltamivir-resistant its public health impact would be substantially worsened. The active metabolite oseltamivir carboxylate (OC) is not removed by sewage treatment and ends up in river water, where OC-concentrations up to 0.86µg/L have been detected. We hypothesize that occasional OC exposure of wild waterfowl carrying IAVs may result in circulation of resistant variants that may potentially evolve to become human-pathogenic. We tested the hypothesis in an in vivo Mallard (Anas platyrhynchos) model in which birds were infected with avian IAVs and exposed to OC. Excreted viruses were analyzed regarding genotypic and phenotypic resistance by neuraminidase (NA) sequencing and a functional NA inhibition assay. Two viruses with NAs of the phylogenetic N2-group, H6N2 and H7N9, acquired the NA substitutions R292K and I222T when host ducks were exposed to 12µg/L and 2.5µg/L of OC, respectively. Drug susceptibilities were at previously described levels for the substitutions. To test persistence of resistance, an OC resistant avian H1N1/H274Y virus (with a group N1 NA-protein) from a previous study, and three resistant H6N2/R292K variants were allowed to replicate in Mallards without drug pressure. Resistance was entirely maintained in the H1N1/H274Y virus, but the H6N2/R292K variants were outcompeted by wild type virus, indicating retained fitness of the resistant H1N1 but not the H6N2 variants. We conclude that OC in the environment may generate resistant IAVs in wild birds. Resistant avian IAVs may become a problem to humans, should the resistance trait become part of a new human pathogenic virus. It implies a need for prudent use of available NAIs, optimized sewage treatment and resistance surveillance of avian IAVs of wild birds.

Anseriformes mantidos em lagos de zôos e parques estão sob constante risco de exposição às doenças presentes nas populações de aves migratórias, que dividem com eles o mesmo local durante um determinado período todos os anos. São doenças que podem ter implicações para as aves cativas, para a população humana que tem contato com essas aves e para os plantéis de produção. Assim, ações de vigilância, com o objetivo de detectar rapidamente determinadas doenças, representam alternativas interessantes para se fazer gestão de risco. O objetivo do presente estudo foi pesquisar a presença de agentes etiológicos selecionados na população de Cisnes Negros (Cygnus atratus), mantida nos lagos da FPZSP, visto que essa população tem contato com as seguintes aves migrantes que visitam a FPZSP todos os anos: irerês (Dendrocygna viduata), marreca caneleira (Dendrocygna bicolor) e marreca asa de seda (Amazoneta brasiliensis). Assim, foram colhidos suabes de traquéia e cloaca de uma amostra capaz de detectar doença com prevalência estimada em 1% para um nível de confiança de 95%. Além disso, foi realizado um estudo retrospectivo (2001 a 2006) das principais causas de morte nessa população. As principais causas de mortalidade registradas em 184 registros analisados foram: desvio de tendão extensor tarso-metatarsiano (37, 20,1%), desnutrição (20, 10,9%), problemas hepáticos (17, 9,2%), traumas (15, 8,2%), problemas respiratórios (8, 4,3%), septicemias (6, 3,3%), intoxicações (5, 2,7%) e problemas gastrointestinais (3, 1,6%). Um terço das carcaças (62, 33,7%) foi encontrado em estado de putrefação. A taxa de mortalidade foi decrescente de 2001 a 2006 e apresentou sazonalidade, sendo maior entre os meses de novembro a maio. No momento das coletas, não houve nenhuma evidência clínica ou laboratorial da presença dos seguintes agentes: Pasteurella multocida., Salmonella sp., Chlamydophila psittaci, Orthomixovírus (Influenza Aviária), Paramixovirus (Doença de Newcastle) e Coronavirus (Bronquite Infecciosa). / Waterfowls housed in ponds of zoos and parks are under constant risk of exposure to pathogens of migratory birds that visit these places every year. Some of them involving zoo animals and humans. The spread of particular diseases may also become a serious threat for domestic poultry. So, surveillance, focused in early detection of some diseases, can be an interesting tool to do risk management. The goal of the present work was to search the presence of some select pathogens in the captive black swan population (Cygnus atratus) present in the ponds of the Fundação Parque Zoológico de São Paulo (FPZSP), because these animals have contact with the following free-living waterfowls: white-faced whistling-duck (Dendrocygna viduata), fulvous whistling-duck (Dendrocygna bicolor) e brasilian teal (Amazoneta brasiliensis). Swabs of trachea and cloaca were sampled from 239 animals, the sample size required for detecting disease present in at least 1% of the animals (CI = 95%). Moreover, a retrospective study was done about the causes of death to the period from 2001 to 2006. The mainly causes of black swan death in FPZSP were: slipped tendon (37/184, 20,1%), malnutrition (20/184, 10,9%), hepatic problem (17/184, 9,2%), trauma (15/184, 8,2%), respiratory problem (8/184, 4,3%), septicemias (6/184, 3,3%), intoxication (5/184, 2,7%) e gastro-intestinal problems(3/184, 1,6%). One third of the carcass (62/184, 33,7%) was in autolysis. The mortality presented peaks of occurrence from november to may and a decreasing trend from 2001 to 2006. At the moment of the sampling, there was no clinical or laboratorial evidence of the infection by the following pathogens: Pasteurella multocida., Salmonella sp., Chlamydophila psittaci, Orthomixovírus (Avian Influenza), Paramixovirus (Newcastle Disease) e Coronavirus (Infectious Bronchitis).

This study was conducted to determine basic data on the incidence of lead shot in ducks us ing the Great Salt Le.lee Basin. The study has been divided into two parts; (1) incidence of ducks carrying lead shot in their tissues and (2) incidenoe of ducks carrying ingested lead shot.

The glaciated prairie pothole country of the Midwest forms a vital segment of the most important waterfowl breeding habitat in North America. Here are hatched three-quarters of all the ducks raised in the United States. During a recent seven-year period the three-state area of Minnesota and the Dakotas produced an average of 4 to 5 million ducks annually (Janzon, 1947). This wetland region which once comprised 115,000 square miles in five states had shrunk to about 56,000 square miles by 19.56 (Lynch, 1956). To maintain the pre,;ent rate of waterfowl production in the face of continued destruction of habitat through drainage and other land use practices detrimental to breeding ducks will require that remaining wet lands, particularly those in public ownership, be developed as much .as possible toward their maximum potential for waterfowl production. In recent years the U. S. Fish and Wildlife Service has excavated several hundred experimental artificial potholes and level ditches on its refuges in the Dakotas and Minnesota. It was believed that these water areas would increase the number of ducks breeding on the refuge marshes by providing additional territorial sites. Before more funds are invested to expand this work it is important to determine the success of the existing development in meeting this objective. This study, to evaluate the artificial pothole and level ditch development, was initiated. in 1957 by the U.S. Fish and Wildlife Service at Lower Souris National Wildlife Refuge in North Dakota. The project was carried out in collaboration with the Utah Cooperative wildlife Research Unit and the Department of Wildlife Management, Utah State University.

Habitat selection theory presumes that organisms are not distributed randomly in their environments because of habitat-specific differences in reproductive success and survival; unfortunately, many previous studies were either unable or failed to look for evidence of processes shaping nest site selection patterns. Furthermore, little is known about adaptive nest site selection in northern environments where habitats often have little vegetation and time and climatic constraints may be pronounced. Therefore, I investigated patterns of nest site selection by common eider ducks (<i>Somateria mollissima</i>) at an island colony in Canadas Eastern Arctic, and looked for evidence of selective processes underlying these patterns by employing experimental and observational techniques.<p>I characterized physical features of (a) non-nest sites (b) active nest sites and (c) unoccupied nest sites that had been used in previous years. Habitat features that distinguished non-nest sites from unoccupied nest sites were also important in distinguishing between active and unoccupied nest sites during the breeding season. Active nest sites were closer to herring gull (<i>Larus argentatus</i>) nests, farther from the ocean and had organic substrates. In general, habitat features associated with nest use were not strongly associated with success after the onset of incubation. Nests near fresh water ponds were more successful in one study year, but in the other two study years successful nests were initiated earlier and more synchronously than were unsuccessful nests. Common eiders settled to nest first near the geographic centre of the colony, whereas sites near the largest fresh water pond were occupied later; distance to ocean had no observable effect on timing of nesting. Nest density was greater farther from the ocean, but timing of nest establishment did not differ between high and low density plots. <p>I tested whether moss or duck down placed in nest bowls could increase nest establishment, or advance laying date. I placed this extraneous material in bowls before nesting and found no difference in likelihood of nest establishment; however, bowls containing duck down were initiated earlier (or had higher survival) than those containing no nesting material. To investigate the role of nest shelter and microclimate in nest site choices and female body condition, I placed plywood nest shelters over established nests. Temperature probes indicated that artificially-sheltered females experienced more moderate thermal environments and maintained higher body weight during late incubation than did unsheltered females. However, few eiders nested at naturally-sheltered sites, possibly because nest concealment increases susceptibility to mammalian predators. My results suggest that eider nest choices likely reflect trade-offs among selective pressures that involve the local predator community, egg concealment, nest microclimate and energy use.

The aim of this study was to examine what impact restored and constructed pounds and wetlands have on waterfowls in the area of Linköping. The birdlife in five constructed wetlands werechosen to investigate if specific factors like age, size and vegetation affected the avian diversity in wetlands. Also, extra focus has been given to the threatened Horned Grebe (Podiceps Auritus), breeding in the studied area. The results showed that the number of species as well as individuals of waterfowl and Horned Grebe changed over time in what might be a result of succession in the wetlands. Comparing the number of birds to the size of the wetlands showed a clear correlation. Larger areas inhabited greater numbers of species and individuals. However, the Horned Grebe showed a reverse result, as they seem to prefer smaller wetlands. Finally, a correlation between the numbers of observed Black-headed gulls and Horned Grebes could be found. When there was a greater number of Horned Grebes observed there was also a greater numbers of gulls present. Possibly the Horned Grebe takes advantage of the Black-headed gull-colony for protection against predators.

Habitat selection theory presumes that organisms are not distributed randomly in their environments because of habitat-specific differences in reproductive success and survival; unfortunately, many previous studies were either unable or failed to look for evidence of processes shaping nest site selection patterns. Furthermore, little is known about adaptive nest site selection in northern environments where habitats often have little vegetation and time and climatic constraints may be pronounced. Therefore, I investigated patterns of nest site selection by common eider ducks (<i>Somateria mollissima</i>) at an island colony in Canadas Eastern Arctic, and looked for evidence of selective processes underlying these patterns by employing experimental and observational techniques.<p>I characterized physical features of (a) non-nest sites (b) active nest sites and (c) unoccupied nest sites that had been used in previous years. Habitat features that distinguished non-nest sites from unoccupied nest sites were also important in distinguishing between active and unoccupied nest sites during the breeding season. Active nest sites were closer to herring gull (<i>Larus argentatus</i>) nests, farther from the ocean and had organic substrates. In general, habitat features associated with nest use were not strongly associated with success after the onset of incubation. Nests near fresh water ponds were more successful in one study year, but in the other two study years successful nests were initiated earlier and more synchronously than were unsuccessful nests. Common eiders settled to nest first near the geographic centre of the colony, whereas sites near the largest fresh water pond were occupied later; distance to ocean had no observable effect on timing of nesting. Nest density was greater farther from the ocean, but timing of nest establishment did not differ between high and low density plots. <p>I tested whether moss or duck down placed in nest bowls could increase nest establishment, or advance laying date. I placed this extraneous material in bowls before nesting and found no difference in likelihood of nest establishment; however, bowls containing duck down were initiated earlier (or had higher survival) than those containing no nesting material. To investigate the role of nest shelter and microclimate in nest site choices and female body condition, I placed plywood nest shelters over established nests. Temperature probes indicated that artificially-sheltered females experienced more moderate thermal environments and maintained higher body weight during late incubation than did unsheltered females. However, few eiders nested at naturally-sheltered sites, possibly because nest concealment increases susceptibility to mammalian predators. My results suggest that eider nest choices likely reflect trade-offs among selective pressures that involve the local predator community, egg concealment, nest microclimate and energy use.