The annual distributions of waterfowl during autumn-winter can influence ecological, environmental, cultural, and economic relationships. We used previously developed Weather Severity Indices (WSI) that explained migration by dabbling ducks in eastern North America and weather data from the North American Regional Reanalysis to develop an open-access internet-based tool (i.e, WSI app) to visualize and query WSI data. We used data generated by the WSI app to determine if the weather known to elicit southerly migration by dabbling ducks had changed, October – April 1979 – 2014.We detected that the amount of area in the Mississippi and Atlantic Flyways with weather severe enough to cause southerly migration decreased during, 1) October – December for Green-winged Teal, 2) December – January for Mallards, American Black Ducks, and Northern Pintails, and 3) February – April for Mallards, American Black Ducks, Gadwall, American Wigeon, Green-winged Teal, and Northern Shoveler. Results are consistent with prior research indicating that weather causing autumn-winter migration of dabbling ducks has become increasingly mild over the last 3 decades. The WSI app enables users to query daily maps and data by species and by Flyway, Joint Venture, Landscape Conservation Cooperative, State, and State Waterfowl Hunting Zones. We encourage those with corresponding data on participation and satisfaction by waterfowl enthusiasts (i.e., birders and hunters) to test for relationships with the WSI because of the implications for conservation funding, especially if autumn-winter weather severity continues to become increasingly mild as predicted.
