Abstract
Predator-protected populations of threatened fauna are important for species conservation, although these animals can quickly become predator naïve and can lack appropriate antipredator behaviour to enable them to persist once released. Controlled predator exposure can improve predator recognition and encourage avoidance behaviour, but little is known about the escape responses or fleeing behaviour of prey species. We compared the escape behaviour of a small marsupial, the burrowing bettong, Bettongia lesueur, between two fenced populations: one that had been purposely exposed to feral cats, Felis catus, while the other had been maintained without exotic predators. To quantify escape behaviour, bettongs were trapped and released into a temporary runway and a threatening stimulus was introduced to encourage them to flee. Measures relating to reactivity (escape initiation), escape speed and flight path (protean characteristics: agility, path irregularity and straightness) were recorded from video footage. Cat-exposed bettongs were significantly heavier than those from the cat-naïve population. We found a significant effect of the interaction of treatment (‘cat-exposed’ or ‘cat-naïve’) and body mass on overall escape behaviour. These differences were attributed to increased reactivity and escape speed in cat-exposed bettongs, but not protean characteristics of their flight path. Cat-exposed bettongs fled at an intensity where body size affected their escape performance (larger animals performed longer bounds and achieved faster speeds), while this body size effect was not evident for cat-naïve animals. This result suggests the cat-naïve animals were not as motivated to flee. Introducing low levels of predation pressure can successfully promote the development of antipredator behaviour through selection and/or individual learning, including a heightened escape response. Controlled predator exposure may be able to address some types of prey naïvety and lead to increased survival outside predator-free sanctuaries.
