SSA - Flight control in birds

Lead Research Organisation: University of Leeds
Department Name: School of Biomedical Sciences

Abstract

Background: Birds display a wide variety of flight behaviours that require different amounts of aerodynamic force. To control and modulate aerodynamic force, birds change their wing kinematics, requiring a complex and co-ordinated recruitment of the wing muscles. The mechanical function of these muscles is expected to change with flight speed and in response to environmental turbulence, and must contribute to variation in metabolic energy consumption with flight speed. The control mechanisms that underlie changes in wing shape and in aerodynamic force are unknown.

Objectives: The overall goal of this project is to understand the control mechanisms and energetic costs associated with changes in wing shape. This will be achieved by quantifying the:
(1) mechanical function of the wing muscles in relation to flight speed and environmental turbulence;
(2) change in 3D wing topology;
(3) metabolic energy expenditure of the wing muscles, relative to overall flight costs
(4) change in flow patterns and aerodynamic forces.

Experimental Approach: Birds will be flown in a variable-speed wind tunnel in both steady and turbulent airflows. Muscle mechanical function will be determined using in vivo measurements of muscle length change, force and activity patterns. Muscle metabolic energy expenditure will be determined by measuring muscle metabolic rate in vitro under simulated in vivo conditions. Wing shape will be measured using synchronised multiple high-speed cameras and photogrammetric techniques. Particle image velocimetry (a flow-visualization technique) will be used to determine flow around wings. Overall flight costs will be determined using respirometry.

Novelty & Timeliness: Most previous studies of animal flight have been performed in simplified flow environments and the effects of environmental turbulence have largely been ignored. Previous research on bird flight muscle physiology has focused on the main power generating muscle (the pectoralis) and only limited information is available on the wing muscles (limited to muscle recruitment patterns). The Leeds wind tunnel facility, combined with the techniques for quantifying muscle mechanical function, energy expenditure and flow velocity distribution during locomotion, is unique.

This project falls directly within the theme of mechanistic biology through its main objective of determining the muscular mechanisms that underlie the complex 3D changes in wing topology required to control flight during manoeuvres and when flying in turbulent air. We will identify the coupling between mechanical performance, energy use and perfusion at the level of individual muscles, providing new insights into the mechanisms determining overall organism performance and metabolic energy expenditure.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M011151/1 30/09/2015 29/09/2023
2105370 Studentship BB/M011151/1 30/09/2018 31/12/2022 Madeleine Inglis