Temporal variation in survival and recovery rates of lesser scaup: A response

We recently analyzed long-term (1951-2011) continental band-recovery data from lesser scaup (Aythya affinis) and demonstrated that harvest rates declined through time, but annual survival rates exhibited no such trends; moreover, annual harvest and survival rates were uncorrelated for all age-sex classes. We therefore concluded that declining fecundity was most likely responsible for recent population declines, rather than changes in harvest or survival. Lindberg et al. () critiqued our conclusions, arguing that we did little more than fail to reject a null hypothesis of compensatory mortality, postulated ecologically unrealistic changes in fecundity, and failed to give sufficient consideration to additive harvest mortality. Herein, we re-summarize our original evidence indicating that harvest has been compensatory, or at most weakly additive, and demonstrate that our analysis had sufficient power to detect strongly additive mortality if it occurred. We further demonstrate that our conclusions were not confounded by population size, band loss, or individual heterogeneity, as suggested by Lindberg et al. (), and we provide additional support for our conjecture that low fecundity played a major role in declining scaup populations during 1983-2006. We therefore reiterate our original management recommendations: given low harvest rates and lack of demonstrable effect on scaup survival, harvest regulations could return to more liberal frameworks, and waterfowl biologists should work together to continue banding lesser scaup and use these data to explore alternative hypotheses to identify the true ecological causes of population change, given that it is unlikely to be excessive harvest. (c) 2017 The Wildlife Society. In this rebuttal to Lindberg et al. (this volume), we defend our assertion that harvest has had minimal impact on survival of lesser scaup, and that population declines during 1983-2006 were most likely caused by lowered fecundity. We emphasize the importance of continued banding and joint analysis of all available data, not just population estimates from the May Breeding Pair and Habitat Survey.