Stopover duration and habitat use of spring-migrating dabbling ducks in the Wabash River Valley, USA

Spring migration is an important and often under-studied period of the waterfowl annual cycle. Stopover sites along migration routes contain habitats and resources required by waterfowl to rest and refuel before continuing north to the breeding grounds. The Wabash River Valley (WRV) in southeastern Illinois provides habitat for over 500,000 dabbling ducks each spring. Despite the heavy use of this region, information regarding stopover duration and habitat use of waterfowl is lacking. Stopover duration, or the length of time an individual spends in a distinct region, is an important metric for waterfowl managers to consider while planning for the needs and required resources of migrating birds. Stopover duration for mallards (Anas platyrhynchos) and green-winged teal (Anas crecca) was approximately 17 days (95% CI: 12.6–22.9 days). This is shorter than current estimates used by conservation planners and may shift objectives. Additionally, mallards and green-winged teal used emergent and woody wetland habitat at rates highly disproportional to the availability of those habitats on the landscape. Both species tended to avoid sites with greater amounts of agricultural in the surrounding landscape, while sites surrounded by greater amounts of open water, upland forest, and upland grassland were more likely to be used. There was also a considerable amount of use in areas under conservation easements, suggesting the importance of these easements in waterfowl management. All of this information will help land managers and conservation planners direct funding to the most important habitats in the WRV and ensure sufficient resources for waterfowl utilizing the region each spring