10.5061/DRYAD.KB8JS06
Ling, Hangjian
Stanford University
McIvor, Guillam E.
University of Exeter
van der Vaart, Kasper
Stanford University
Vaughan, Richard T.
Simon Fraser University
Thornton, Alex
University of Exeter
Ouellette, Nicholas T.
Stanford University
Data from: Local interactions and their group-level consequences in
flocking jackdaws
Dryad
dataset
2019
corvids
flocking
social interactions
3D Imaging
Biophysics of locomotion
collective behaviour
2019-06-10T14:28:16Z
2019-06-10T14:28:16Z
en
https://doi.org/10.1098/rspb.2019.0865
180916660 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
As one of nature’s most striking examples of collective behaviour, bird
flocks have attracted extensive research. However, we still lack an
understanding of the attractive and repulsive forces that govern
interactions between individuals within flocks and how these forces
influence neighbours’ relative positions and ultimately determine the
shape of flocks. We address these issues by analysing the
three-dimensional movements of wild jackdaws (Corvus monedula) in flocks
containing 2 to 338 individuals. We quantify the social interaction forces
in large, airborne flocks and find that these forces are highly
anisotropic. The long-range attraction in the direction perpendicular to
the movement direction is stronger than that along it, and the short-range
repulsion is generated mainly by turning rather than changing speed. We
explain this phenomenon by considering the wingbeat frequency and the
change in the kinetic and gravitational potential energy during flight,
and find that changing the direction of movement is less energetically
costly than adjusting speed for birds. Furthermore, our data show that
collision avoidance by turning can alter local neighbour distributions and
ultimately change the group shape. Our results illustrate the macroscopic
consequences of anisotropic interaction forces in bird flocks, and help to
draw links between group structure, local interactions, and the biophysics
of animal locomotion.
Movie S1Original images captured by one of the four cameras and the
reconstructed birds’ 3D movement trajectories for flock
#1.MovieS1.aviMovie S2Original images captured by one of the four cameras
and the reconstructed birds’ 3D movement trajectories for flock
#2.MovieS2.aviMovie S3Original images captured by one of the four cameras
and the reconstructed birds’ 3D movement trajectories for flock
#3.MovieS3.aviMovie S4Original images captured by one of the four cameras
and the reconstructed birds’ 3D movement trajectories for flock
#4.MovieS4.aviMovie S5Original images captured by one of the four cameras
and the reconstructed birds’ 3D movement trajectories for flock
#5.MovieS5.aviMovie S6Original images captured by one of the four cameras
and the reconstructed birds’ 3D movement trajectories for flock
#6.MovieS6.aviData S1Bird id number, position, time, velocity,
acceleration, and wingbeat frequency at every time step for flocks #1 to
6.DataS1.txtData S2Bird id number, position, time, velocity, acceleration,
and wingbeat frequency at every time step for 305 isolated pairs (bird ids
1&2, 3&4, 5&6, and so on are two birds from a same
pair).DataS2.txtcode