Revealing the drivers of space use patterns in a bird population using mechanistic modelling

As wild animals advance through their available habitat, interactions with other organisms and their environment occur. These interactions influence movement decisions, giving rise to complex space use patterns across landscapes. Untangling the behavioural drivers of movement is therefore critical in understanding animal space use and ultimately in managing the conservation of ecosystems. Some animals restrict their movement to a limited area of their available habitat, known as a home range. This thesis uses mechanistic modelling to uncover the behavioural drivers behind home range formation in of a population of long-tailed tits.

Long-tailed tits (Aegithalos caudatus) are small, non-territorial passerines, commonly found in Europe. Flocks live in partly-exclusive home ranges, patterns which are unusual amongst non-territorial animals. This thesis shows
that a combination of memory-mediated conspecific avoidance and a response to the deciduous woodland can adequately explain the observed home range patterns. Furthermore, I show that the avoidance mechanism depends upon kin-relatedness and flock size. Finally, I investigate the birds’ fine-scale selection for different types of trees whilst foraging within their breeding home ranges. I reveal a set of preferred foraging trees and how the population of birds are selecting them.

Overall, the conclusions and methods throughout this thesis advance not only our knowledge of long-tailed tits but exemplify the application of mathematics to understand ecological processes.