Skip to main content
Dryad

Data for: Flying through gaps – How does a bird deal with the problem and what costs are there?

Henningsson, Per1

Published Jul 29, 2021 on Dryad. https://doi.org/10.5061/dryad.rr4xgxd8j

Data files

Jul 29, 2021 version files 81.23 MB

Abstract

Animals flying in the wild often show remarkable abilities to negotiate obstacles and narrow openings in complex environments. Impressive as these abilities are, this must result in costs in terms of impaired flight performance. In this study, I used a budgerigar as model for studying these costs. The bird was filmed in stereo when flying through a wide range of gap widths from well above wingspan down to a mere 1/4 of wingspan. 3D flight trajectories were acquired and speed, wingbeat frequency and accelerations/decelerations were calculated. The bird used two different wing-postures to get through the gaps and could use very small safety margins (down to 6mm on either side) but preferred to use larger when gap width allowed. When gaps were smaller than wingspan flight speed was reduced with reducing gap width down to half for the smallest and wingbeat frequency was increased. I conclude that flying through gaps potentially comes with multiple types of cost to a bird of which the main may be: i) reduced flight speed increases the flight duration and hence the energy consumption to get from point A to B, ii) the underlying U-shaped speed to power relationship means further cost from reduced flight speed, and associated with it iii) elevated wingbeat frequency includes a third direct cost.