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What drives long-distance movements in the nomadic Grey Teal Anas gracilis in Australia?

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journal contribution
posted on 01.01.2008, 00:00 authored by David RoshierDavid Roshier, M Asmus, Marcel KlaassenMarcel Klaassen
In contrast to northern temperate environments, where day length and temperature changes are obvious proximate cues for movement to resource-rich breeding habitats, the cues for movement used by birds in an often resource-poor, stochastic environment are less obvious. We recorded long-distance movements of 23 Grey Teal Anas gracilis using satellite telemetry for up to 879 days and examined the relationship between those movements and environmental factors, such as heavy rainfall and flooding, at the destination site. We identified 32 long-distance [> 150 km) movements that met our criterion for minimally interrupted flight between origin and destination. Thirteen of these flights coincided with rainfall and/or flooding events up to 1050 km from the origin. However, some ducks moved without any clear beneficial conditions at the destination onto small wetlands in regions with little surface water. The data suggest that there are two types of long-distance movement - ranging and directed. These flights occurred over distances up to 1200 km across the arid inland. The rates and distances of movement suggest that long-distance movements of Grey Teal entail high energy costs as in waterfowl elsewhere. We conclude that the proximate controls of directIn contrast to northern temperate environments, where day length and temperature changes are obvious proximate cues for movement to resource-rich breeding habitats, the cues for movement used by birds in an often resource-poor, stochastic environment are less obvious. We recorded long-distance movements of 23 Grey Teal Anas gracilis using satellite telemetry for up to 879 days and examined the relationship between those movements and environmental factors, such as heavy rainfall and flooding, at the destination site. We identified 32 long-distance (> 150 km) movements that met our criterion for minimally interrupted flight between origin and destination. Thirteen of these flights coincided with rainfall and/or flooding events up to 1050 km from the origin. However, some ducks moved without any clear beneficial conditions at the destination onto small wetlands in regions with little surface water. The data suggest that there are two types of long-distance movement – ranging and directed. These flights occurred over distances up to 1200 km across the arid inland. The rates and distances of movement suggest that long-distance movements of Grey Teal entail high energy costs as in waterfowl elsewhere. We conclude that the proximate controls of directed movements need not be very different from those of their temperate counterparts.ed movements need not be very different from those of their temperate counterparts.

History

Journal

Ibis: the International Journal of Avian Science

Volume

150

Issue

3

Pagination

474 - 484

Publisher

Wiley-Blackwell

Location

Oxford, England

ISSN

0019-1019

eISSN

1474-919X

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2008, British Ornithologists’ Union