QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chai, P. Search for Related Content PubMed PubMed Citation Articles by Chai, P. Social Bookmarking                         What's this?

Journal of Experimental Biology, Vol 200, Issue 10 1527-1536, Copyright © 1997 by Company of Biologists

JOURNAL ARTICLES

Hummingbird hovering energetics during moult of primary flight feathers

P Chai
Department of Zoology, University of Texas, Austin 78712, USA. pengchai@utxvms.cc.utexas.edu

How does a hovering hummingbird compensate for the loss of flight feathers during moult when the mechanism of lift force generation by flapping wings is impaired? The flight performance of five individual ruby-throated hummingbirds with moulting primary flight feathers and reduced wing area was compared with that before their moult. Hummingbirds were flown in reduced air densities using normoxic heliox so that a range of flight energetics was displayed. The rate of moulting and the extent of wing area loss varied among individuals. One female could tolerate a 30% loss of wing area in moulting and flew with only three outer primaries per wing. Further exploratory study using the artificial reduction of wing area, either by cutting the tips of the outer primaries of a male or by plucking the secondaries of two females, suggested that secondaries play a minor role in lift force generation during hovering whereas the tip area of primaries is crucial. For the five birds, ranges of whole-bird oxygen consumption rates, wingbeat kinematics (stroke amplitude) and lift coefficients did not vary during the moult. This constancy was mainly achieved through weight loss that alleviated aerodynamic force requirements for weight support during hovering. Since the metabolic power expenditure during moult was similar to that of normal birds but the mechanical power requirement was reduced, the flight efficiency also showed a sharp reduction during moult. This increased cost of flight may result from disruption of the integrity of the flight machinery. Overall, the control of body mass in hummingbirds can provide similar aerodynamic, muscle mechanical and physiological capacities under conditions of variable flight demand.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				C. J. Clark and R. Dudley Flight costs of long, sexually selected tails in hummingbirds Proc R Soc B, June 7, 2009; 276(1664): 2109 - 2115. [Abstract] [Full Text] [PDF]

				K. C. Welch Jr, D. L. Altshuler, and R. K. Suarez Oxygen consumption rates in hovering hummingbirds reflect substrate-dependent differences in P/O ratios: carbohydrate as a `premium fuel' J. Exp. Biol., June 15, 2007; 210(12): 2146 - 2153. [Abstract] [Full Text] [PDF]

				S. P. Roberts, J. F. Harrison, and R. Dudley Allometry of kinematics and energetics in carpenter bees (Xylocopa varipuncta) hovering in variable-density gases J. Exp. Biol., February 22, 2004; 207(6): 993 - 1004. [Abstract] [Full Text] [PDF]

				D. L. Altshuler and R. Dudley The ecological and evolutionary interface of hummingbird flight physiology J. Exp. Biol., August 15, 2002; 205(16): 2325 - 2336. [Abstract] [Full Text] [PDF]

				R. Dudley Mechanisms and Implications of Animal Flight Maneuverability Integr. Comp. Biol., February 1, 2002; 42(1): 135 - 140. [Abstract] [Full Text] [PDF]

				A HedenstrOM and S Sunada On the aerodynamics of moult gaps in birds J. Exp. Biol., January 1, 1999; 202(1): 67 - 76. [Abstract] [PDF]