Investigating social dynamics using automated radiotracking of winter flocks of Black-capped chickadees (Poecile atricapillus)
Abstract
The major forces that govern social groups, namely fission-fusion dynamics, cohesion and maintenance, are nearly ubiquitous across animal groups. The field of animal collective behaviour has recently been married with automated radiotracking producing a ‘re-wilding’ of field research into sociality. The combination of this with Social Network Analysis has led to discoveries such as population wide information transfer and the flexibility of animal groups to change social connectivity based on environmental context. However, these networks are constructed, and do not include the dynamic environmental, spatio-temporal, and social contexts which directly affect sociality. I conducted the first automated radiotracking study I know of to track free-living flocks of black-capped chickadees, through the non-breeding season. My major objective was to combine existing radiotelemetry methods with advanced statistical techniques to create novel methodologies to track and quantify socially relevant movements and behaviours. Firstly, I used Linear Discriminant Analysis to match signal strength profiles of key individuals to all others as a new method of flock identification. Secondly, I examined onset of daily activity to test whether this was cohesive in flocks. Since unexpected spikes of early activity prior to onset were observed, I investigated the possibility that these restless events were related to environmental stressors. Finally, I used known activity thresholds to investigate the general activity patterns of ranks to address previous contradictions of rank and activity, and to test if field activity was consistent with theoretical predictions of optimal winter bird activity. Flocks were effectively tracked and identified with automated radiotelemetry alone and fusion-fission events could be tracked as well. Onset of activity was found to be cohesive within flocks, which was further supported by onset changes during fission-fusion events. Environmental pressure, temperature, windspeed and winter storm events were all related to sleep disturbances. Daily activity amount was higher in high ranks than low ranks and general activity patterns agreed with theoretical models. My findings contribute new methodologies to the field of collective animal movement and demonstrate the importance of automated radiotelemetery studies in providing important applications to social dynamics and beyond.