Accelerometry predicts muscle ultrastructure and flight capabilities in a wild bird

Area of Science:

• Avian biology
• Animal physiology
• Ecological energetics

Background:

• Muscle ultrastructure significantly influences athletic performance in terrestrial animals.
• Locomotion is vital for wild animals' survival and reproduction, yet direct links to muscle condition in wild populations are scarce.
• Understanding muscle-flight dynamics in wild birds is crucial for movement ecology.

Purpose of the Study:

• To investigate the relationship between flight behavior and muscle ultrastructure in breeding black-legged kittiwakes (Rissa tridactyla).
• To assess the impact of muscle biopsy sampling on kittiwake reproductive success and survival.

Main Methods:

• Utilized GPS-accelerometers to record flight behavior (wing beat frequency, airspeed).
• Collected muscle biopsies to analyze muscle fiber diameter and nuclei number.
• Compared reproductive success and over-winter survival between biopsied and non-biopsied individuals.

Main Results:

• Muscle fiber diameter showed a negative association with wing beat frequency, suggesting larger fibers support powered flight.
• The number of nuclei per muscle fiber positively correlated with average airspeed, indicating a need for muscle plasticity in faster flight.
• No significant impact of muscle biopsy on reproductive success or survival was observed.

Conclusions:

• Flight behavior parameters can potentially predict muscle ultrastructure in wild birds.
• Muscle fiber size and nuclearity are key adaptations for efficient flight in black-legged kittiwakes.
• The study provides a methodological basis for future research on wild animal muscle physiology and behavior.