Habitat use of spring migrating dabbling ducks in the Wabash River Valley, USA

Stopover sites provide crucial habitat for waterfowl to rest and refuel during migration. Knowledge of which land-cover types are of greatest importance to migrating waterfowl and how the surrounding landscape influences their use can inform management decisions and conservation plans to adequately meet resource requirements. Specifically, spring migration habitat is essential for waterfowl preparing for breeding yet is an understudied period of the life cycle. We placed radio-transmitters on Mallards (Anas platyrhynchos) and Green-winged Teal (Anas crecca) between January and April 2016-2017 in the Wabash River Valley of Illinois and Indiana to assess habitat use and movement patterns. Both Mallards and Green-winged Teal primarily used emergent and woody wetlands, with 89% of use points in these land-cover types even though they made up <5% of the study area. Use of both dry and flooded row crops was minimal. While habitat selection of Mallards was similar for diurnal vs. nocturnal periods, Green-winged Teal used emergent wetlands at a higher rate during the day and shifted to woody wetlands at night. In general, sites surrounded by greater amounts of open water, upland forest, and upland herbaceous/grassland cover were more likely to be used than areas surrounded by row-crop agriculture. Additionally, private and public lands enrolled in conservation easement programs (such as the Wetlands Reserve Program) were frequently used by migrating waterfowl compared to other protected or public lands. These findings highlight the importance of a landscape-level approach to conservation, specifically focusing on wetland restoration while minimizing reliance on agricultural fields to fulfill habitat needs during spring migration in the Midwest.