Diet dichotomy between two migrant seabirds breeding near a high Arctic polynya

• Published in: Royal Society Open Science
• Main Authors: Isabeau Pratte, Kelly A. Boadway, Shanti E. Davis, Mark Maftei, Mark L. Mallory
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2017
• Subjects: niche segregation; stable isotopes; sabine's gull; arctic tern; incubation; Science; Q; Arctic; Arctic tern; Sabine's Gull; Sterna paradisaea; Xema sabini
• Online Access: https://doi.org/10.1098/rsos.160982; https://doaj.org/article/dcc7d23fdc594f4eb1c9b077ec3cee76

High Arctic polynyas are predictable areas of open water, which offer long-distance migrant seabirds a reliable source of food during a period when they have to replenish and accumulate energy for reproduction. Investigating the interaction between species nesting sympatrically in the vicinity of polynyas should provide insights into the role that such oceanographic features play for pre-breeding seabirds. We used stable isotopes (δ13C and δ15N) to compare the diet of two ground-nesting seabirds, Sabine's gull (Xema sabini) and Arctic tern (Sterna paradisaea), nesting on an island adjacent to a recurring polynya in the Canadian high Arctic in 2008 and 2009. We show that, unlike Arctic terns, the diet of Sabine's gulls appears to include a non-negligible amount of terrestrially derived prey during early incubation, and that overall both species segregate their dietary niche during pre-laying and early incubation.