The first tracking data for juvenile Hudsonian Whimbrel

There is evidence of a decline in the Whimbrel population on the West Atlantic Flyway. As efforts continue to identify the causes of decline, juvenile migration ecology and survival has been identified as a key information gap. In 2015, we launched a study to address this on a flyway scale. We deployed satellite and GPS transmitters on juvenile Whimbrel captured on Cape Cod, Massachusetts, USA, a southbound staging area used by both juvenile and adult Whimbrel. Using the transmitter data, we established migratory connectivity between Cape Cod and other sites along juvenile Whimbrel migration routes. We documented Whimbrel movement patterns during migration and on their non-breeding grounds, including non-breeding home ranges and a delayed maturation period of up to 2.5 years. We also identified nocturnal roosts on Cape Cod, which researchers can use for long-term monitoring of adult and juvenile birds. The current study has laid the groundwork for launching a full-scale, follow-on study of juveniles at this site. This could collect demographic data, such as survival and recruitment, which will contribute to a demographic model that will help identify priorities for conservation action on a hemispheric scale.