Comparing autumn duck use of intensely managed wetlands in Michigan using a novel approach

Socioeconomic value derived from duck hunting has contributed to autumn habitat use becoming a particular focus for the natural resource community. Land managers work to promote waterfowl and hunting by providing energy‐rich food resources across the landscape that attract and concentrate individuals while mitigating disturbance by providing spatial and temporal sanctuary. Questions remain on how ducks distribute themselves on the landscape during autumn migration, which overlaps harvest windows. We compared 2018 and 2019 autumn duck use on 6 areas in southeastern Michigan, USA, and assessed relationships with associated vegetation (natural marsh or farmed fields), hunting status (whether a location was open to hunting or not), diel period, and season progression. We employed a novel camera trap survey method and used a subset of our data to compare estimates derived from motion‐triggered and time‐lapse camera settings. Generally, use was greater in areas closed to hunting (sanctuary) as compared to hunted locations. Similarly, use of fields was typically greater than use of marshes. However, these relationships were modified by an interaction between diel period and season progression. Motion‐trigger and time‐lapse methods generated similar estimates, indicating both are viable options for duck use comparisons. We encourage natural resource managers to promote a suite of vegetation types on the landscape and to maintain or expand areas of sanctuary for autumn duck use.