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

The behaviour of captive mallards (Anas platyrhynchos) and black ducks (Anas rubripes) was studied from the end of March to mid-June in 1991 and 1992 to determine the extent of interspecific aggression exhibited and the effect of sympatry and allopatry on interactions between the two species. / Mallards were more aggressive than black ducks regardless of sex and origin, though both species were equally attacked in both years, male ducks were more aggressive and more attacked than female ducks regardless of species and origin in both years, and ducks of sympatric origin were more aggressive than ducks of allopatric origin in 1991 regardless of sex and species while the opposite was true in 1992. / Site attachment was observed in 7 of 9 experiments performed in 1992. In the experiments involving site attachment, almost all of the activity centered around the feeding stations, not around the nesting platforms.

Habitat use by sympatric black ducks (Anas rubripes) and mallards (A platyrhynchos) was studied in Abitibi, Quebec during May-August 1988 and 1989. / Black duck broods preferred emergent and shrub-rich areas in both years. Mallard broods' habitat use differed from 1988 to 1989 (from emergent to shrub-emergent areas) when average water levels were higher. Diversity of habitats seems more important to rearing black ducks than to mallards. Rearing mallards seem to modify their use of habitats according to changing habitat availability. Daily survival rates differed only slightly between "species". / Telemetry was used to study wetland use by six mallard and three black duck non-breeding females. Swamps were preferred whereas ericaceous shrub wetlands were avoided by both "species". Beaver (Castor canadensis) ponds were extensively used during the moulting period. Home ranges averaged 302.7 ha for black ducks and 201.2 ha for mallards.

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Several factors have contributed to impeding the progress of migratory waterfowl spatial modeling, such as (1) waterfowl’s reliance on wetlands, (2) lack of understanding about shifts in distributions through time, and (3) large-scale seasonal migration. This doctoral dissertation provides an array of tools to address each of these concerns in order to better understand and conserve this group of species. The second chapter of this dissertation addresses issues of modeling species dependent on wetlands, a dynamic and often ephemeral habitat type. Correlation models of the relationships between climatic variables and species occurrence will not capture the full habitat constraints of waterfowl. This study introduces a novel data source that explicitly models the depth to water table, which is a simulated long-term measure of the point where climate and geological/topographic water fluxes balance. The inclusion of the depth to water table data contributes significantly to the ability to predict species probability of occurrence. Furthermore, this data source provides advantages over traditional proxies for wetland habitat, because it is not a static measure of wetland location, and is not biased by sampling method. Utilizing the long-term banding bird data again, the third chapter examines the behavior of waterfowl niche selection through time. By using the methods developed in chapter two, probability of occurrence models for the 1950s and the 1990s were developed. It was then possible to detect movements in geographic and environmental space, and how movements in these two spaces are related. This type of analysis provides insight into how different bird species might respond to environment changes and potentially improve climate change forecasts. The final chapter presents a new method for predicting the migratory movement of waterfowl. The method incorporates not only the environmental constraints of stopover habitat, but also includes likely distance and bearing traveled from a source point. This approach uses the USGS’ banding bird database; more specifically, it relies on banding locations, which have multiple recoveries within short time periods. Models made from these banding locations create a framework of migration movement, and allow for predictions to be made from locations where no banding/recovery data are available. / text

Military jet over-flight activities pose a potential threat to staging waterfowl and pilots. The migration period is important for nutrient acquisition and courtship as these waterfowl enter the breeding season. Using a focal animal (continuous) technique for five-minute intervals, diurnal Time/Activity (TA) budgets for Canada Geese (Branta canadensis canadensis) (n=751), American Black Duck (Anas rubripes) (n=474) and Common Goldeneye (Bucephala clangula) (n=1274) were compiled during 216 hours of behavioural observation. The study was conducted from 26 April to 27 May, 2002 at the outlet of Lac Fourmont, Labrador (52° 03' 30"N, 60° 31' 01" W), in an ashkui or area of open water in an otherwise frozen landscape, which is known historically as a place to hunt waterfowl. These staging grounds are within the 130 000 km2 Low-level Training Area (LLTA) of the Quebec-Labrador Peninsula. Generalized Linear Modeling (GLM) of ranked variables was used to analyze behaviour by: observer, sex, pair status, time of day, date, and each weather parameter. Male Common Goldeneye spent more time in courtship behaviours (2.7%) than females (1.1%) and they spent most of the daylight hours feeding (males 53.3% and females 54.5%), with little time resting (4.8% and 5.2%, respectively). In contrast, Black Ducks and Canada Geese spent relatively little time feeding (12.4% and 5% respectively) and most of their time sleeping (35% and 38% respectively) and locomotion (37.8% and 11% respectively). Ashkui are important to Common Goldeneyes for foraging, and to Canada Geese and Black Ducks for resting prior to the breeding season. / Ninety-one low-level jet over-flights occurred and sound levels (n=336 h) at the study site were measured. Effects of low-level jet over-flights were analyzed using GLM of ranked variables in order to analyze a number of variables simultaneously. All behavioural observations that occurred in the quarter hour periods up to 165 minutes after an over-flight were analyzed. Alert and courtship behaviours of Canada Geese increased after over-flights. Other behaviours were negatively affected to a lesser degree. Locomotor activities by Black Ducks increased significantly immediately following over-flights with a stronger movement response with increased noise. Increases in agonistic and comfort behaviours of Common Goldeneye were detected following over-flights with few other significant affects on their behaviour. / Key words. Anas rubripes, Branta canadensis, Bucephala clangula, disturbance, jet aircraft, Labrador, low-level flying, military activity, noise, spring staging, time-activity budgets, waterfowl

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