Open Collections

Ciocca, Francesca

University of British Columbia

The ability of birds to change their wing shape allows them to perform complex aerial behaviours. This mechanism, known as wing morphing, affords control over efficiency, stability, and maneuverability during flight. Previous comparative work has shown that dynamic, rather than static, metrics of wing shape are associated with flight behaviour, implying that diverse ecological pressures have caused interspecific variation in wing morphing capacity. However, one aspect of wing morphing has received little attention in the flight biomechanics literature: the propatagium. This region of skin, muscles, and tendons between the shoulder and the wrist has been hypothesized to generate more lift than the skeletal and feather components of the wing, and adjustments to its shape and surface area could affect aerodynamic forces experienced by the bird. Although the propatagium has been informally observed to change shape during wing flexion and extension, its morphing has never been quantified. Here I described how 3D propatagium morphology changes over the wing’s range of motion and across 14 avian species. Propatagium shape was significantly affected by both elbow and wrist angles, but to varying degrees, suggesting an interactive mechanism of skeletal control. Static propatagium shape showed strong phylogenetic signal, but dynamic morphing metrics were not strongly influenced by phylogeny, implying that propatagial morphing, like wing range of motion itself, may instead relate to other factors like flight ecology. Quantification of these metrics provides a basis for further comparative work on dynamic propatagium morphology, as well as investigation of the propatagium’s aerodynamic properties.

Text

2023-08-25

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85635

Zoology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/