Evol Ecol Res 1: 443-457 (1999)     Full PDF if your library subscribes.

Fitness components of avian migration: A dynamic model of Western Sandpiper migration

Colin W. Clark1 and Robert W. Butler2

1Institute of Applied Mathematics, The University of British Columbia, Vancouver, British Columbia V6T 1Z2 and 2Pacific Wildlife Research Centre, Canadian Wildlife Service, 5421 Robertson Road, Delta, British Columbia V4K 3N2, Canada

Author to whom all correspondence should be addressed.
e-mail: biec@interchange.ubc.ca

ABSTRACT

Western Sandpipers, Calidris mauri, one of the world’s most abundant shorebird species, migrate from winter sites in the southern USA and Central and South America to breeding grounds in Western Alaska and Eastern Siberia. We describe a dynamic state variable optimization model for these migrations, assuming that individual female sandpipers employ migration strategies that maximize their expected lifetime reproduction. The principal environmental factors assumed to affect migration decisions are variable wind speeds, site-specific predation risks, and the timing of food availability on the breeding grounds and at the two most northerly stopover sites. The model’s predictions, which agree closely with data collected in the field, are most sensitive to changes in wind conditions during the flight phase, rather than foraging opportunities at stopover sites en route. We also show how the model can be used to assess potential impacts of habitat degradation on the fitness of this species.

Keywords: avian migration, dynamic optimization models, habitat degradation and fitness loss, predation risk, Western Sandpipers.

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        © 1999 Colin W. Clark. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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