Movement predictability of individual barn owls facilitates home range size and survival estimation

Abstract Background. There is growing attention to individuality in movement, its causes and consequences. Accumulating evidence demonstrates that conspecifics differ repeatably in their spatial behaviors, forming behavioral types (“spatial-BTs”), similarly to other well-established personality traits (e.g., boldness or sociability). Spatial-BTs are typically described as the difference in the mean level among individuals, while the intra-individual variation (IIV, i.e., predictability) is only rarely considered. Studies identifying the factors that determine predictability or its ecological consequences for broader space use patterns are even more sparse, in part because it was mostly tested in captivity (e.g., with repeated boldness assays). Here we test if [i] individuals differ in their movement and specifically in their predictability. We then investigate [ii] the consequences of this variation for home range size and survival estimates, and [iii] the factors that affect individual predictability. Methods. We tracked 92 barn owls (Tyto alba) at very high resolution (every few seconds) using an ATLAS system, and monitored their survival. We calculated movement and space-use indices (e.g., max-displacement and home-range size, respectively) from the trajectories (115.2 ± 112.1 nights; X̅±SD) and then used double-hierarchical and general mix models to assess spatial-BTs, individual predictability in nightly max-displacement, and its consistency across time. Finally, we explored if predictability levels were associated with home-range estimates and survival, as well as the seasonal and demographic factors (age, sex) that affect it. Results. Our dataset revealed clear patterns of individualism in owls’ movement. Individuals differed consistently both in their mean movement (e.g., max-displacement) and their IIV around it (i.e., predictability). Further, more predictable individuals had smaller home-ranges and lower survival rates, on top and beyond the expected effects of their spatial-BT (max-displacement), sex, and age. Juveniles were less predictable than adults, but sexes did not differ in their predictability. Conclusion. These results demonstrate that individual predictability may act as an overlooked axis of spatial-BT with potential implications for relevant ecological processes at the population level and individual fitness. Considering how individuals differ in their IIV of movement beyond the mean-effect can facilitate understanding the intraspecific diversity, predicting their responses to changing ecological conditions and their population management.