Spring stopover sites used by the Red Knot Calidris canutus roselaari in Alaska, USA: connectivity between the Copper River Delta and the Yukon-Kuskokwim River Delta

With an estimated population of 22,000 individuals, the Red Knot Calidris canutus roselaari is one of the least-studied shorebird populations in North America. Historically, limited ground-based counts of Red Knots on the Copper and Yukon-Kuskokwim river deltas in Alaska suggested these two regions were major stopover areas during spring migration. To further document connectivity, occurrence, local movements, and length of stay, we attached VHF transmitters to 70 adult Red Knots at Grays Harbor, Washington, and conducted aerial telemetry surveys at the Copper and Yukon-Kuskokwim river deltas. We relocated 84% and 70% of the marked birds at the Copper and Yukon-Kuskokwim river deltas, respectively, signifying a high level of connectivity between Grays Harbor and the two Alaska sites during spring migration. We identified areas previously not known to be important for Red Knots, including Controller Bay on the Copper River Delta and the southern coast of the Yukon-Kuskokwim River Delta. Short length of stay suggests that both study areas function primarily as stopover areas.