A Comprehensive Analysis of the Hunting Behavior of Reintroduced Leopards (Panthera pardus ciscaucasica) in the Russian Caucasus

In the context of the Persian leopard restoration program in the Russian Caucasus, an in-depth analysis was conducted to understand the hunting behaviors of rewilded Persian leopards and evaluate the program’s effectiveness. From 2016 to 2023, GPS telemetry data from 14 leopards (8 males and 6 females) aged 20 months and older, released in the Western (WeC) and Central (CeC) Caucasus, were analyzed. Using cluster location analysis, we determined 243 kill sites categorized by prey-size into large, medium, and small classes. In the WeC, leopards exhibit a significantly higher proportion of large prey compared to the CeC (43%, N = 49 vs. 5.4%, N = 148, p < 0.01). There is no significant difference in the proportion of medium-sized prey, but there is a striking contrast in the proportion of small prey (WeC 16.2%, CeC 57.4% (p < 0.01)). No significant differences were found in the time spent on prey between male and female leopards, regardless of the region. Female leopards capture their next prey 215 ± 184 hours (Mean ± SD; N = 131) after leaving the previous one, covering a distance of 46 ± 40 km (Mean ± SD, max 191 km). Male leopards, in contrast, take 265 ± 246 hours (Mean ± SD, N = 110) between kills, with a distance of 59 ± 60 km (Mean ± SD, max 366 km) between them. In the WeC, the kill rate for leopards are lower than in the CeC, with averages of a prey every 264 ± 273 hours and 62 ± 64 km (N = 77) compared to 152 ± 172 hours and 47 ± 41 km (N = 165), respectively. Leopards in the CeC spend significantly more time on kill sites with large and medium-sized prey compared to small prey. In contrast, leopards in the WeC show no significant difference in the time spent on prey of different size classes. This disparity is explained by the fact that large and medium-sized prey are more challenging to conceal and defend from competitors whose populations densities are higher in the WeC than the CeC. 20% of large and medium-size prey kill sites of leopard in the Western Caucasus have been visited by bears or wolves. This suggests that environmental factors and attractive high ungulate population densities may also play a critical role in shaping predator-prey dynamics and interspecific competition in the region. It is imperative to evaluate the availability of potential prey across different size classes, alongside with moderate levels of competitor populations. These factors can play a decisive role during the crucial first year of the leopard’s adaptation to life in the wild, ultimately determining the success of species restoration initiatives.