Harvest Mortality of Mallards (Anas platyrhynchos) Banded at Lake St. Clair, CAN and Western Lake Erie, USA

Abstract

Coastal marshes of Lake St. Clair, in southwest Ontario, CAN and Lake Erie, in northwest Ohio, USA are important migratory staging locations for waterfowl despite experiencing substantial wetland losses. Waterfowl habitat management at these locations focuses on providing food resources for Mallards (Anas platyrhynchos), a highly sought game species. We examined direct recovery rates of Mallards banded prior to the 2014, 2015, and 2016 hunting seasons as a measure of harvest mortality. We compared harvest mortality between the two locations, among years, among four sex and age cohorts, and as a function of body condition. We found that banding location for juvenile Mallards was an important variable predicting harvest mortality. The probability of being a direct recovery was 126% greater for juvenile females and 70% greater for juvenile males banded at Lake St. Clair compared to those banded in northwest Ohio. Average body condition was slightly less for juvenile male Mallards banded in northwest Ohio during 2016 compared to those banded in 2015 or those banded in LSC in 2014 or 2015. We did not detect any other significant differences related to body condition and location or location-year with respect to direct recovery rates. We hypothesize that harvest mortality of juvenile Mallards could be related to differences in harvest regulations, bird abundances, or hunter density between the two study sites, all of which may have different implications for those interested in managing Mallard populations in the lower Great Lakes region.