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Body building and concurrent mass loss: flight adaptations in tree sparrows
1Department of Zoology, Stockholm University, SE 106 91, Stockholm, Sweden. johan.lind@zoologi.su.se
Proceedings. Biological Sciences
|September 21, 2001
Summary
Tree sparrows exhibit remarkable organ flexibility during molting. They rapidly adjust body and pectoral muscle mass to maintain flight efficiency despite reduced wing area, showcasing strategic physiological adaptations.
Area of Science:
- Avian physiology
- Phenotypic plasticity
- Evolutionary biology
Background:
- Environmental changes drive physiological flexibility.
- Organ size regulation in birds shows plasticity.
- Limited research exists on organ flexibility in non-migratory species.
Purpose of the Study:
- Investigate physiological adaptations to increased wing loading during natural molt in tree sparrows (Passer montanus).
- Explore organ flexibility patterns in a non-migratory species.
- Understand the strategic adjustments birds make to maintain flight performance.
Main Methods:
- Utilized non-invasive techniques to study tree sparrows during their natural molting period.
- Measured changes in pectoral-muscle size and body mass relative to wing area.
- Conducted experimental manipulations to assess rapid physiological responses.
Main Results:
- The ratio of pectoral-muscle size to body mass increased as wing area decreased during molt.
- This ratio decreased after molt completion.
- Tree sparrows experimentally reduced body mass and increased pectoral-muscle size within 7 days in response to reduced wing area.
Conclusions:
- Demonstrated a novel, strategic organ-flexibility pattern in tree sparrows.
- This rapid adjustment contrasts with typical body mass-muscle size coupling.
- Suggests the paramount importance of flight in birds drives such adaptations, even in non-migratory species.