Ecology of Male Black Ducks Molting in Labrador
- Bowman, Timothy D.
University of Maine Graduate School
Most waterfowl undergo an annual simultaneous wing molt and are flightless for 3-5 weeks. Information on the molt for black ducks (Anus Rubripes) is lacking. This study provides baseline information on the ecology of male black ducks during the wing molt. During the summers of 1983-1986, I captured molting black ducks by hand in Oak Bay, Labrador. No black ducks were found nesting and 98% of all ducks captured were male. Flightless black ducks were found most often in willow (Salix sp.) (40% of all sites), but also were frequently located in shoreline cavaties (14%) and emergent herbaceous vegetation (14%) near freshwater wetlands. only 12% used saltwater habitats. Sites used by molting black ducks were often far from open water (e.g., x=12 m for willow sites). Male black ducks may use certain microhabitats and remain sedentary during the wing molt to avoid predators, benefit thermodynamically, and conserve energy needed for growth of new flight feathers.
Fidelity of black ducks to molting areas was documented. Twenty-nine banded male black ducks were captured molting on the study area in 2 different years, and 3 molting birds were captured in 3 consecutive years. Of those ducks recaptured, 52% molted on the same pond where they molted in a previous year. When assumed natural mortality and crippling loss are considered, an estimated minimum of 10% of the surviving ducks returned to the molting area 1 year after banding. Returning birds not observed would raise this figure even higher.
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