Altitude and temperature effects on the energetic cost of hover-feeding in migratory rufous hummingbirds,Selasphorus rufus
- 1 March 2008
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Zoology
- Vol. 86 (3), 161-169
- https://doi.org/10.1139/z07-127
Abstract
During migratory stopovers, rufous hummingbirds ( Selasphorus rufus (Gmelin, 1788)) can achieve high daily rates of net energy intake and mass gain while foraging at a range of elevations and ambient temperatures, despite the high energetic costs of hovering flight and thermoregulation. To gain insights into the factors affecting the energetic costs incurred during foraging, we captured migratory hummingbirds and measured their oxygen consumption rates during hover-feeding. Measurements were performed in situ where rufous hummingbirds forage as they migrate at several locations along a gradient in elevation and over the range of ambient temperatures normally experienced. Oxygen consumption rates during hover-feeding varied between the sexes and between juveniles and adults. These differences appeared to reflect differences in the power requirements for hovering flight in relation to variation in wing morphology. Decreasing ambient temperature and increasing elevation both significantly increased oxygen consumption rate during hover-feeding. The effects of these two environmental variables were additive, suggesting that hummingbird thermoregulatory requirements were not met by the additional heat produced by the higher metabolic rate necessary to support hovering flight at higher elevation. These results provide insight into the ways different foraging strategies may allow hummingbirds to maximize net energy intake.Keywords
This publication has 29 references indexed in Scilit:
- Oxidation rate and turnover of ingested sugar in hovering Anna's(Calypte anna) and rufous (Selasphorus rufus)hummingbirdsJournal of Experimental Biology, 2007
- Oxygen consumption rates in hovering hummingbirds reflect substrate-dependent differences in P/O ratios: carbohydrate as a `premium fuel'Journal of Experimental Biology, 2007
- Of Hummingbirds and Helicopters: Hovering Costs, Competitive Ability, and Foraging StrategiesThe American Naturalist, 2004
- Energy regulation by traplining hummingbirdsFunctional Ecology, 1999
- Limits to vertebrate locomotor energetics suggested by hummingbirds hovering in helioxNature, 1995
- The aerodynamics of hovering insect flight. VI. Lift and power requirementsPhilosophical Transactions of the Royal Society of London. B, Biological Sciences, 1984
- On the temperature-dependency of optimal nectar concentrations for birdsJournal of Theoretical Biology, 1979
- Elevation and the Morphology, Flight Energetics, and Foraging Ecology of Tropical HummingbirdsThe American Naturalist, 1979
- Community Organization Among Neotropical Nectar-Feeding BirdsAmerican Zoologist, 1978
- The Flight of Birds: The Significant Dimensions, Their Departure from the Requirements for Dimensional Similarity, and the Effect on Flight Aerodynamics of That DepartureTransactions of the American Philosophical Society, 1975