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B.2-5: Behavioral multipliers to resting metabolic rate in black ducks and lesser scaup

Presented by Jacob McPherson - Email: jmcpherson@ducks.org

American black duck (Anas rubripes) and lesser scaup (Aythya affinis) are species of concern within North American Waterfowl Management Plan goals. Historic declines in these populations may be the result of multiple factors including resource availability on migration and wintering landscapes. Bioenergetics modeling is used to calculate the carrying capacity of a landscape by estimating energy demand and energy supply. Estimates for physiologic parameters required in calculating energetic demand (i.e. resting metabolic rates [RMR] and behavioral specific multipliers) have relied on limited research. The primary objective of this project is to produce estimates of behavior specific multipliers to RMR to improve estimates of daily energy requirements in black ducks and lesser scaup. We used open-flow respirometry techniques to estimate RMR and to isolate behavior specific factorial increases to RMR in each of these species. RMR and behavioral multipliers estimated in this study were different from those reported in previous studies. Further, we found that multiplier estimates for certain behaviors in each species were similar enough to one another to justify combining behaviors into homogenous groups representing high, medium, and low energy behavior classes. As expected, the following covariates were found to have significant effects on energy expenditure associated with certain behaviors in one or both species: weight of bird, sex of bird, water temperature, time of day, presence of food, and presence of other birds. Results from this study technologically improve past estimates and simplify the underlying calculations required for bioenergetics modeling by combining behaviors with statistically similar energetic demands and will help improve the accuracy of landscape carrying capacity estimates resulting from those models.
Session: Energetics & Habitat (Tuesday, August 27, 13:20 to 15:00)