Citizen science generates reliable migration chronologies to supplement professional surveys for waterfowl habitat management

ABSTRACT Targeted monitoring by trained professionals has been the standard to inform evidence-based regulatory and conservation planning decisions for migratory waterfowl and other wildlife in North America. As inferential expectations derived from professional surveys grow and funding wanes, decision-makers are turning toward citizen science as supplemental or alternative data sources. However, external validation of citizen science data, in cooperation with experts, is recommended before their use in management decisions. We compiled data from professional surveys across 7 U.S. states within the Upper Mississippi / Great Lakes Joint Venture (JV) for 16 species of waterfowl (ducks, geese, and swans) to compare with and potentially validate temporal trends in weekly relative abundance predictions (i.e., migration curves) by eBird citizen science data. We demonstrated that eBird weekly relative abundance produced similar migration curves to those derived from professional surveys for most species. Concordance between migration curves for uncommon or vagrant species was less reliable, especially at the county level. However, at spatial scales more relevant for regulatory or conservation planning decisions (e.g., state or JV scale), correlation between eBird and professionally derived migration curves increased to adequate levels of concordance for most species (p ≥ 0.70). We concluded that eBird weekly relative abundance is a suitable supplement to professional surveys to generate migration curves for waterfowl conservation planning during the nonbreeding season. Additionally, states and JVs that lack monitoring at appropriate temporal frequency may consider using eBird relative abundance to derive migration chronologies for priority species that are well-distributed throughout their region. Broadly, we encourage continued external validation of citizen science data—which requires close partnership between researchers and decision-makers—for its wise use in management decisions.