Roads, risk and routine: how leopard (Panthera pardus) and black-backed jackal (Lupulella mesomelas) time their road use relative to vehicles in three South African conservation properties

How carnivores time their road use relative to vehicles in African conservation areas remains poorly understood. We examined the on-road activity of leopard (Panthera pardus) and black-backed jackal (Lupulella mesomelas) relative to vehicles at three South African conservation properties spanning a 24-fold range in vehicle activity, with blue wildebeest (Connochaetes taurinus) as a diurnal comparator. Wildebeest tracked diurnal vehicle activity at every property, whereas both carnivores were most active when vehicles were scarce and overlapped vehicle activity far less than the comparator. Jackal overlap was lowest at the property with the heaviest traffic. Leopards overlapped vehicles less than jackals where traffic was lighter, but this reversed where traffic was heaviest, a descriptive pattern we did not test. Neither carnivore appeared later than expected after vehicle passages where records sufficed for the test, mainly at the heaviest-traffic property, so we found no evidence of an immediate response to vehicles. The only fine-scale signal was the expected aggregation of the comparator. Because both carnivores are naturally nocturnal, their low daytime overlap with vehicles is consistent with, but not evidence of, avoidance. Road use relative to vehicles differed between species and among sites and was not a simple function of traffic volume.