Stopover duration of spring migrating dabbling ducks in the Wabash river valley

Waterfowl use stopover sites during spring migration to rest and replenish nutrient reserves prior to their arrival on breeding grounds. Estimating the extent to which an individual remains at a stopover site before dispersing (i.e., stopover duration) is essential for managers to develop wetland habitat objectives needed to ensure sufficient resources are available to meet the needs of migrating waterfowl. Our objectives were to determine average stopover duration of dabbling ducks in the Wabash River Valley (WRV) of Illinois and Indiana, USA, identify factors that may influence that duration, and evaluate how those duration values compare with those currently used by the Upper Mississippi River and Great Lakes Region Joint Venture (UMRGLRJV). We estimated stopover duration of 39 mallard (Anas platyrhynchos) and 62 green-winged teal (A. crecca) between January and April 2016–2017 in the WRV. Estimated stopover duration for mallards and green-winged teal was 17.0 days (95% CI = 12.6–22.9). Our estimate is substantially shorter than current estimates used by the UMRGLRJV for conservation planning and could affect conservation objectives for waterfowl.