Understanding the effects of seasonal variation in prey availability on prey switching by large carnivores

Optimal foraging theory predicts that carnivores select prey species based on intrinsic factors, such as body size, vulnerability, and abundance. Prey abundance can vary significantly, especially when prey species move in and out of an area en masse in search of food. However, little is known about how these resource pulses influence the prey profiles of large carnivores. Using data on lion (Panthera leo) and cheetah (Acinonyx jubatus) kills in the Maasai Mara in Kenya, we investigate whether changes in prey abundance, as a result of a mass annual migration of herbivores, influence the prey profiles of these two carnivore species. Furthermore, for cheetah we investigate whether there are sex-specific differences in prey profiles in response to changes in prey abundance. Using data from 387 lion kills and 220 cheetah kills (160 female and 60 male), we found that changes in prey abundance had a strong influence on prey profiles, but that for cheetahs this varied by sex and social grouping. More specifically, during the migration, when there is an influx of wildebeest (Connochaetes taurinus), lions and male cheetah (particularly those in coalitions) were more likely to feed on wildebeest than out of the migration. In addition, when wildebeest were less abundant, lions switched to buffalo (Syncerus caffer). Overall, the breadth of the prey profiles was narrower during the migration compared to out of the migration but this was most significant for lions and coalitions of male cheetahs. These changes in prey profiles could have an impact on herbivore dynamics, human-wildlife conflict and ecological interactions more broadly. Through the detailed characterisation of prey profiles, we contribute to the understanding of predator-prey dynamics and trophic interactions in complex, multi-species ecosystems and illustrate the importance of taking into account inter- and intraspecific variations in predators when modelling predator-prey dynamics.