High-tide flight by wintering Dunlins (Calidris alpina): a weather-dependent trade-off between energy loss and predation risk
Abstract:Migratory shorebirds wintering or staging on ocean coasts collect at high tide on roosting sites that remain above the flood line. However, some species of Calidris sandpipers spend the high-tide interval in flight over the ocean. In the winters of 2006–2012, the characteristics of high-tide flight by Dunlins (Calidris alpina (L., 1758)) were studied at Boundary Bay, British Columbia, Canada. At wind speeds of 1–6 m/s, flocks of Dunlins remained airborne over the ocean for up to 4 h at altitudes of >30 m. If winds were >10 m/s, the Dunlins coursed low over the waves. Ambient temperature was a significant determinant in the occurrence and duration of high-tide flight. In October and November, the Dunlins spent just as much time in flight before as after high tide, but in January, flight duration was 43% shorter after high tide than before high tide. The mean January temperatures were significantly lower than in October and November. The Dunlins were hunted by Peregrine Falcons (Falco peregrinus Tunstall, 1771), which captured 81 prey in 494 attacks. The maximum kill rate of 0.28 captures per hour of observation was recorded in the second hour after high tide, which suggests that predation risk is greatest for Dunlins that return early from high-tide flight.
Keywords: Calidris alpina; Dunlins; Falco peregrinus; Peregrine Falcon; bécasseaux variables; dépendance de la météo; faucon pèlerin; high-tide flight; predation risk; risque de prédation; vol à marée haute; weather dependence
Document Type: Research Article
Publication date: January 1, 2013
- Published since 1929, this monthly journal reports on primary research contributed by respected international scientists in the broad field of zoology, including behaviour, biochemistry and physiology, developmental biology, ecology, genetics, morphology and ultrastructure, parasitology and pathology, and systematics and evolution. It also invites experts to submit review articles on topics of current interest.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Terms & Conditions
- Sample Issue
- Reprints & Permissions
- ingentaconnect is not responsible for the content or availability of external websites