Availability and use of protected areas by nine Cape vultures at the overall and core home range scales.

The proportion of each vulture’s 99% kernel density estimated (KDE) contour occupied by protected areas (PAs) defined their availability (Ai) to each vulture. At the overall home range scale use (Ui) of protected areas was defined as the proportion of stationary (i.e. ·h−1) GPS locations within the 99% KDE contour that were recorded inside protected areas. The proportion of each vulture’s 50% KDE contours occupied by protected areas defined their use at the core foraging range scale. Ivlev’s electivity index values range from –1 to +1, with zero indicating use in proportion to availability, while positive and negative values indicate use more or less than expected, respectively.