Measuring leg thrust forces in the common starling

Area of Science:

• Biomechanics
• Avian biology
• Animal locomotion

Background:

• Understanding the biomechanics of avian takeoff and landing is crucial for studying flight.
• Previous research has focused on wing kinematics, but less on the ground reaction forces involved.

Purpose of the Study:

• To design and utilize a force-transducing perch to quantify the ground reaction forces during takeoff and landing in small birds.
• To investigate the relationship between these forces, body mass, and force angles.
• To explore the potential ecological implications of variations in takeoff and landing strategies.

Main Methods:

• Development of a novel force-transducing perch capable of measuring multi-axial reaction forces.
• Recording takeoff and landing events of common starlings (Sturnus vulgaris).
• Analysis of force magnitude, direction, and correlation with individual body mass.

Main Results:

• Landing forces were significantly lower than takeoff forces in common starlings.
• Both takeoff and landing forces showed a significant positive correlation with body mass.
• The angles of the reaction forces were not significantly dependent on body mass and lacked repeatability within individuals.

Conclusions:

• The observed differences in force exertion suggest distinct strategies for landing and takeoff, with wing-assisted deceleration during landing.
• Body mass is a key determinant of takeoff and landing forces, but not force direction.
• The variability in force angles may reflect diverse locomotor strategies that could serve as an anti-predator mechanism.