Variation in resource use between adult and juvenile Semipalmated Sandpipers (Calidris pusilla) and use of physiological indicators for movement decisions highlights the importance of small staging sites during southbound migration in Atlantic Canada

• DOI: 10.3389/fevo.2022.1059005
• Publication Date: 2022-12-22T13:12:51Z
• Authors: Rebeca C. Linhart; Diana J. Hamilton; Julie Paquet; Sara C. Bellefont...; Siena Davis; Parker B. Doiron; Cheri L. Gratto-T...
• Keywords: Calidris; Sandpiper

Semipalmated Sandpipers ( Calidris pusilla ) are Arctic-breeding shorebirds that use staging sites in Atlantic Canada during their annual migration to South America. The Bay of Fundy has long been recognized as a critical site for migrating and supports large prey base. diet adult sandpipers the is flexible but juveniles, which arrive later, not well documented. Comparatively little known about base how it utilized by at outside Bay. Plasma metabolite measures can provide useful insight assess habitat quality have yet measured Canada. To address these knowledge gaps we sampled shorebird estimate invertebrate availability Northumberland Strait. Concurrently, collected blood samples from juvenile analysis plasma levels isotopic estimates dietary niche both regions. We found on Strait hosted more diverse variable than within Fundy, were selective when foraging there, appearing prefer bivalves. Juveniles may occupy broader adults along Strait, though appear gain weight efficiently. had higher triglyceride concentrations those suggest differences fattening rate or fat intake. lower likely move into while with high values tended remain These data made movement decisions region depending physiological state. Our results successfully variety habitats This an encouraging finding sandpiper conservation region, also indicates maintaining access broad critical, supporting calls stronger throughout region.