Abstracts

Presented by Drew Fowler - Email: drew.fowler@wisconsin.gov

Mallards are the most heavily harvested duck species in the Mississippi Flyway (MF), including the Great Lakes states and these birds help support over 2.5 million duck hunter-days in the MF annually. Harvests of mallards originating from breeding areas in the Great Lakes Region are managed as part of the Mid-continent mallard population via Adaptive Harvest Management and mallard harvests within Great Lakes states have been derived largely from birds breeding within the Great Lakes region. We studied historic patterns of mallard abundance in the Mid-continent mallard breeding area based on spring waterfowl breeding population and habitat surveys. Great Lakes mallard abundance increased over the long-term and breeding mallard abundance in the Great Lakes States historically followed trends of the remainder of the Midcontinent population; however, trends diverged when Great Lakes mallards failed to recover from low abundance in the mid-2000s. Studies of hunting regulations, harvest rates, and hunter participation failed to find links to reduced mallard abundance; also, mallard productivity appears to have been relatively stable over the long-term in the Great Lakes region. Survival models fit to band recovery data showed little evidence harvest was excessive or that survival declined. Mallard abundance in Michigan has been positively related to Great Lakes water levels and this relationship was believed to reflect regional changes in wetland hydrology and availability of breeding habitat. The relationship of mallard abundance with water levels weakened after 2007 and abundance has not recovered despite water level recovery. Waterfowl biologists in Michigan and other Great Lakes states are at a loss to explain the current low mallard abundance as apparently suitable habitat has gone unoccupied. It is possible breeding distribution of mallards in the MF has changed and we propose a study of philopatry, movements, survival, and productivity in relation to mallard habitat selection and genetics.