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A puzzling migratory detour : are fueling conditions in Alaska driving the movement of juvenile sharp-tailed sandpipers?

journal contribution
posted on 01.02.2011, 00:00 authored by A Lindstrom, R Gill Jr., S Jamieson, B McCaffery, L Wennerberg, M Wikelski, Marcel KlaassenMarcel Klaassen
Making a detour can be advantageous to a migrating bird if fuel-deposition rates at stopover sites along the detour are considerably higher than at stopover sites along a more direct route. One example of an extensive migratory detour is that of the Sharp-tailed Sandpiper (Calidris acuminata), of which large numbers of juveniles are found during fall migration in western Alaska. These birds take a detour of 1500-3400 km from the most direct route between their natal range in northeastern Siberia and nonbreeding areas in Australia. We studied the autumnal fueling rates and fuel loads of 357 Sharp-tailed Sandpipers captured in western Alaska. In early September the birds increased in mass at a rate of only 0.5% of lean body mass day-1. Later in September, the rate of mass increase was about 6% of lean body mass day-1, among the highest values found among similar-sized shorebirds around the world. Some individuals more than doubled their body mass because of fuel deposition, allowing nonstop flight of between 7100 and 9800 km, presumably including a trans-oceanic flight to the southern hemisphere. Our observations indicated that predator attacks were rare in our study area, adding another potential benefit of the detour. We conclude that the most likely reason for the Alaskan detour is that it allows juvenile Sharp-tailed Sandpipers to put on large fuel stores at exceptionally high rates.

History

Journal

Condor

Volume

113

Issue

1

Pagination

129 - 139

Publisher

University of California Press, Journals Division

Location

Berkeley, Ca.

ISSN

0010-5422

eISSN

1938-5129

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2011, The Cooper Ornithological Society