Effect of Winter-diet Restriction on Prebasic Molt in Female Wood Ducks

During winters 1990-1992, we manipulated food availability 5%-20% less than that of ad libitum feeding for captive groups of wild-strain North American wood ducks (Aix sponsa) to test effects of increasing levels of food restriction on prebasic molt of females. Birds fed ad libitum and 5%-15% restricted diets exhibited a protracted molt (>90 days) of low intensity. Most females fed a 20%-restricted diet did not initiate molt until resumption of ad libitum food availability. We hypothesize that a 20% restriction exceeds a threshold in food availability and possibly body condition needed by captive female wood ducks to meet nutritional demands of maintenance and prebasic molt. A lower threshold may exist for free-living wood ducks, implying the importance of adequate food availability and quality during winter to minimize negative effects on within- and cross-seasonal life-cycle functions. We encourage continued conservation of bottomland hardwood forests in southeastern United States because of their intrinsic values to sustaining populations of wood ducks in North America.

Starting page
506
Ending page
516
ID
6780