Morphological and physiological aspects of takeoff aptitudes of female common eiders (Somateria mollissima) during the pre-laying period

• Published in: Canadian Journal of Zoology
• Main Authors: Ouellet, J.-F., Guillemette, M., Blier, P. U.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2008
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Somateria mollissima
• Online Access: http://dx.doi.org/10.1139/z08-021; http://www.nrcresearchpress.com/doi/full-xml/10.1139/Z08-021; http://www.nrcresearchpress.com/doi/pdf/10.1139/Z08-021

In many bird species, follicular growth and the accumulation of body reserves may impair flight takeoff capability of breeding females. The pre-laying period in common eiders, Somateria mollissima (L., 1758), is characterized by a dramatic sex-specific takeoff impairment, and we tested the hypothesis that pre-laying female common eiders compensate to diminish or delay their takeoff impairment. We addressed our question at three organizational levels: (1) measurement of wing morphology, (2) mass of flight musculature, and (3) measurement of the activity of key enzymes of aerobic and glycolytic capacity in one locomotor muscle and one structural muscle. All measurements were performed on individuals of both sexes. We found that wing area was similar between sexes despite males being structurally larger. Our results also indicate that female mass gain is partly compensated by higher pectoralis mass, while the catalytic capacity of the tissue remains unchanged. We conclude that females diminish and delay their takeoff impairment differently according to organizational levels.