Data from: fission-fusion dynamics in sheep: the influence of resource distribution and temporal activity patterns

Fission-fusion events, i.e. changes to the size and composition of animal
social groups, are a mechanism to adjust the social environment in
response to short-term changes in the cost-benefit ratio of group living.
Furthermore, the time and location of fission-fusion events provide
insight into the underlying drivers of these dynamics. Here, we describe a
method for identifying group membership over time and for extracting
fission-fusion events from animal tracking data. We applied this method to
high-resolution GPS data of free-ranging sheep (Ovis aries). Group size
was highest during times when sheep typically rest (mid-day and at night),
and when anti-predator benefits of grouping are high while costs of
competition are low. Consistent with this, fission and fusion frequencies
were highest during early morning and late evening, suggesting that social
restructuring occurs during periods of high activity. However, fission and
fusion events were not more frequent near food patches and water resources
when adjusted for overall space use. This suggests a limited role of
resource competition. Our results elucidate the dynamics of grouping in
response to social and ecological drivers, and we provide a tool for
investigating these dynamics in other species.