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American black ducks (Anas rubripes), a once plentiful species in northeastern North America, have been in decline for over half a century due to habitat loss, hybridization with mallards (Anas platyrhynchos), and historic overhunting. While the overall population of black ducks has stabilized and even increased in portions of its range, important wintering areas in western Pennsylvania and West Virginia have continued to see a decrease. Our objectives were to determine wintering black duck daily energy expenditure (DEE) in Central Appalachia through time-activity budgets, and calculate behavioral differences among wetland systems, levels of naturalness, management schemes, flock composition, year, date, and time of day. Between November and March 2015‒2016 and 2016‒2017, we conducted waterfowl surveys twice a month and recorded diurnal time-activity budgets when black ducks were encountered. We calculated DEE using both a simple cost of thermoregulation model (684.94 kJ/bird/day) and a complex (1,542.95 kJ/bird/day) cost of thermoregulation model incorporating site-level wind speeds and temperatures. Swimming was the most dominant behavior overall (35.2%), followed by foraging (26.2%), and sleeping (16.4%). Black ducks foraged the most in natural wetlands (56%) and riverine systems (34%) and swam the most in modified (43%) and created (26%) wetlands. Black duck behavior varied greatly within wetland systems, management schemes, and levels of naturalness. As such, we recommend wetland and waterfowl managers incorporate the complex cost of thermoregulation DEE model for more accurate estimations of duck use days, and provide a diversity of nearby habitat types with differing levels of management for wintering waterfowl to meet their multitude of needs throughout the winter.

Wintering American Black Duck Ecology of Central Appalachia