How do spotted hyaenas respond to decreased prey availability in their clan territories over the last decades?

Climate change can alter predator-prey dynamics by influencing the distribution and movements of migratory prey. Despite increasing research on predator-prey mismatches, how predators respond to changes in prey availability caused by climate change remains largely unknown, particularly for behaviourally flexible species such as central-place foragers. In the Serengeti National Park, Tanzania, increased rainfall in recent decades is thought to have altered the movement patterns of large herds of migratory herbivores, the main prey of spotted hyaenas (Crocuta crocuta) in the park, leading to a decrease in yearly migratory prey presence within hyaena clan territories. Between 1990 and 1994, migratory prey were present within hyena clan territories for about 12% of the year--mainly in May-June and November-December--dropping to just 7% between 2015 and 2019. Using longitudinal data from three Serengeti hyaena clans at the centre of the park monitored between 1990 and 2019, we investigated the impact of the observed decrease in migratory prey presence on the number of observations of hyaenas feeding at carcasses ("feeding events", n = 777), and explored associated changes in hyaena clan size. The vast majority of observed hyaena feeding events involved migratory prey species, with this relative proportion remaining constant throughout the study period. Annual patterns in the number of feeding events closely mirrored annual patterns of migratory prey presence in clan territories, with two distinct peaks mid-year and toward the end of the year. As migratory prey presence in the study clan territories declined over the years, the number of observed feeding events also decreased. However, the size of two out of three clans increased over time, suggesting that the decline in migratory prey presence in clan territories and in the number of observed feeding events did not negatively impact hyaena clans. This absence of decline in clan size may reflect the fact that hyaenas feed within their territories for only a small fraction of the year, although it also invites further investigation into the mechanisms hyaenas may employ to compensate for reduced prey availability and reduced feeding events within their clan territories.