Carrying large fuel loads during sustained bird flight is cheaper than expected

Research output: Contribution to journalArticle

Abstract

Birds on migration alternate between consuming fuel stores during flights and accumulating fuel stores during stopovers. The optimal timing and length of flights and stopovers for successful migration depend heavily on the extra metabolic power input (fuel use) required to carry the fuel stores during flight(1,2). The effect of large fuel loads on metabolic power input has never been empirically determined. We measured the total metabolic power input of a long-distance migrant, the red knot (Calidris canutus), flying for 6 to 10 h in a wind tunnel, using the doubly labelled water technique(3). Here we show that total metabolic power input increased with fuel load, but proportionally less than the predicted mechanical power output from the flight muscles. The most likely explanation is that the efficiency with which metabolic power input is converted into mechanical output by the flight muscles increases with fuel load. This will influence current models of bird flight and bird migration. It may also help to explain why some shorebirds, despite the high metabolic power input required to fly, routinely make nonstop flights of 4,000 km longer(4).

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Subject classification (UKÄ) – MANDATORY

  • Ecology
Original languageEnglish
Pages (from-to)730-732
JournalNature
Volume413
Issue number6857
Publication statusPublished - 2001
Publication categoryResearch
Peer-reviewedYes

Related research output

Anders Kvist, 2001, Department of Ecology, Lund University. 126 p.

Research output: ThesisDoctoral Thesis (compilation)

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