Dynamic body acceleration increases by 20% during flight ontogeny of greylag geese Anser anser

Marie Claire Gatt,Yachang Cheng,Michael Quetting,Martin Wikelski

doi:10.1111/jav.02235

Abstract

Despite our knowledge of the biophysical and behavioural changes during flight ontogeny in juvenile birds, little is known about the changes in the mechanical aspects of energy expenditure during early flight development, particularly in migratory species. Here, we investigate in a unique experimental setup how energy expended during flights changes over time beginning with early ontogeny. We calculate overall dynamic body acceleration (ODBA) as a proxy for energy expenditure in a group of hand raised greylag geese Anser anser trained to fly behind a microlight aircraft. We propose two potential hypotheses; energy expenditure either increases with increasing physiological suitability (the ‘physical development hypothesis’), or decreases as a result of behavioural improvements mitigating flight costs (the ‘behavioural development hypothesis’). There was a significant temporal increase of flight duration and ODBA over time, supporting the ‘physical development hypothesis’. This suggests that early on in flight ontogeny behavioural development leading to flight efficiency plays a weaker role in shaping ODBA changes than the increased physical ability to expend energy in flight. We discuss these findings and the implications of flight development on the life history of migratory species.

Highlights

Konstanzer Online-Publikations-System (KOPS) URL: http://nbn-resolving.de/urn:nbn:de:bsz:352-2-1nneh9jcow3l9The study of the development of flight in birds has been notably concerned with the biophysical and behavioural changes experienced by juveniles in an attempt to draw parallels with the evolution of flight (Dial et al 2006, Heers et al 2011, 2014, Heers and Dial 2012, Heers 2016)
To assess the respective importance of these two nonmutually exclusive hypotheses in early flight development, we investigated the relationship between energy expenditure and age over the first 10 weeks of flight
The relationship between overall dynamic body acceleration (ODBA) and age is stronger when analysing the first four 50 s segments of cruising flight separately (Fig. 3, Table 2), over which ODBA increases up to around 20% over the course of the study. It appears that ODBA gradually decreases throughout the duration of flight (F = 32.695, df = 3, p-value

Summary

Introduction

The study of the development of flight in birds has been notably concerned with the biophysical and behavioural changes experienced by juveniles in an attempt to draw parallels with the evolution of flight (Dial et al 2006, Heers et al 2011, 2014, Heers and Dial 2012, Heers 2016). About the changes in the energetic cost of flying over the first weeks of flight experienced in young birds. We analyse how energy expenditure during flight changes during ontogeny in a group of hand-raised greylag geese Anser anser trained to fly behind a microlight aircraft. Flight development has consequences on social cohesion and movement ecology, more so in migratory populations in preparation for longer autumn migratory displacements (Yésou 1991, Andersson et al 2007)

Methods

Results

Conclusion