Characterization of bird formations using fuzzy modelling

Abstract

The investigation of the emergent collective behaviour in flying birds is a challenging task, yet it has always fascinated scientists from different disciplines. In the attempt of studying and modelling line formation, we collected high-precision position data of 29 free-flying northern bald ibises ( Geronticus eremita ) using Global Navigation Satellite System loggers, to investigate whether the spatial relationships within a flock can be explained by birds maintaining energetically advantageous positions. Specifically, we exploited domain knowledge and available literature information to model by means of fuzzy logic where the air vortices lie behind a flying bird. This allowed us to determine when a leading bird provides the upwash to a following bird, reducing its overall effort. Our results show that the fuzzy model allows to easily distinguish which bird is flying in the wake of another individual, provides a clear indication about flying flock dynamics and also gives a hint about birds' social relationships.

The Aerodynamic Mechanisms of the Formation Flight of Migratory Birds: A Narrative Review

“…The first theoretical studies [28] were often carried out with simplifications, as the experimental facilities of the time were unable to quantify the forces exerted on the birds' wings, or to obtain precise information on the relative positions of the birds in relation to each other. It was only with the development of biologgers, capable of measuring energy expenditure, body movements (accelerometers), and individual positioning (GPS), that many of the key ideas could be tested [44][45][46]. One study, also considered pioneering for its experimental approach conducted with birds in flight, was carried out by Weimerskirch et al [13].…”