Barrier interactions
To understand hyena behavior around fences and determine the locations of weak or robust fences on the protected area boundaries, we used the Barrier Behavior Analysis (BaBA) methodology developed by Xu et al. (2020). BaBA examines whether, where, and how often animal movements were altered by linear barriers such as fences by classifying movement trajectories within set buffers around target barriers into normal movement (quick cross , average movement), altered movement (bounce , trace , or back and forth ), and trapped movement. To assess the appropriate sensitivity for the BaBA results, we used BaBA with 50m, 100m, and 150m fence buffer distances within which GPS locations were classified as fence encounters (Xu et al. 2020).
Finally, to supplement our understanding of hyena interactions with and crossing of the boundary fences, we used images of spotted hyenas from camera traps placed on sixteen key crossing points at the LNNP fence from June 2018 - November 2019 (see Wilkinson et al. 2021b for detailed methodology). Spotted hyenas in camera trap images were individually identified using spot patterns and compared to individuals previously listed in both the LNNP and Soysambu Conservancy hyena ID books (see Supporting Information). Hyenas appearing at the fence were first compared to the clan with a range closest to the camera trap site but then expanded to all others in the book if not identified. The hyena was labeled as unknown if we could not definitively identify the individual. These unknown individuals were later added to the Lake Nakuru or Soysambu Conservancy ID Books under a new ID code and used for further identification of images. We assessed the frequency of fence approaches at each site and by specific individuals, as well as the number of different fence crossing sites visited by each individual.