Assessing geographic origins of Teal (Anas crecca) through stable-hydrogen (δ 2H) isotope analyses of feathers and ring-recoveries

Abstract

Management of migratory game birds must be considered at the flyway scale. Flyway delineation has generally relied on ring recoveries, yet migratory connectivity between breeding and wintering grounds is often difficult to demonstrate due to low ring-recovery rates. To overcome the limitations of ring recoveries, we here relied on stable-hydrogen isotope ratios (δ2H) from feathers of 939 hunted Teal (Anas crecca) in France in the winters of 2002–2003 to 2005–2006 to determine the geographic origin of these individuals. Likelihood-based assignment analyses, including the use of Bayesian priors based on ring recoveries, suggest that Teal wintering in France mostly originate from Russia, up to the Ural Mountains, and to a lesser extent from Finland. This suggests that more collaboration with Russia for the management of Teal in Europe should be encouraged. Our study identifies Teal breeding hotspots, which should receive greater research and monitoring attention. Our isotope assignment results can be used as a reference value in time against which future similar analyses could be compared, potentially to track geographic shifts linked with habitat and climate change.