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- Kvist, Anders, et al.
(författare)
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Carrying large fuel loads during sustained bird flight is cheaper than expected
- 2001
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 413:6857, s. 730-732
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Piersma, T, et al.
(författare)
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High daily energy expenditure of incubating shorebirds on High Arctic tundra: a circumpolar study
- 2003
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Ingår i: Functional Ecology. - : Wiley. - 1365-2435 .- 0269-8463. ; 17:3, s. 356-362
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Tidskriftsartikel (refereegranskat)abstract
- 1. Given the allometric scaling of thermoregulatory capacity in birds, and the cold and exposed Arctic environment, it was predicted that Arctic-breeding shorebirds should incur high costs during incubation. Using doubly labelled water (DLW), daily energy expenditure (DEE) during incubation was measured in eight shorebird species weighing between 29 and 142 g at various sites in the Eurasian and Canadian High Arctic. The results are compared with a compilation of similar data for birds at lower latitudes. 2. There was a significant positive correlation between species average DEE and body mass (DEE (kJ day(-1) )=28.12 BM (g)(0.524) , r(2)=0.90). The slopes of the allometric regression lines for DEE on body mass of tundra-breeding birds and lower latitude species (a sample mostly of passerines but including several shorebirds) are similar (0.548 vs 0.545). DEE is about 50% higher in birds on the tundra than in temperate breeding areas. 3. Data for radiomarked Red Knots for which the time budgets during DLW measurements were known, indicated that foraging away from the nest on open tundra is almost twice as costly as incubating a four-egg clutch. 4. During the incubation phase in the High Arctic, tundra-breeding shorebirds appear to incur among the highest DEE levels of any time of the year. The rates of energy expenditure measured here are among the highest reported in the literature so far, reaching inferred ceilings of sustainable energy turnover rates.
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