In situ predator exposure creates some persistent anti-predator behaviours: insights from a common environment experiment

Abstract

Prey naiveté has been implicated in the global decline and reintroduction failure of many threatened species. A number of tools have been developed to combat prey naiveté including in situ predator exposure using live predators. However, determining the effectiveness and persistence of these interventions can be difficult, and requires comparisons of individual responses from predator-naïve and predator-trained populations. Even when this occurs, interpreting behavioural responses can be challenging because of the constraints of experimental design in large scale population manipulations. We used a common environment experiment and placed burrowing bettongs (Bettongia lesueur) from predator-free and predator-exposed populations together in an 8 ha fenced paddock. The predator-exposed population had been previously exposed to feral cats (Felis catus) under controlled wild conditions for up to six years and initial work suggested this exposure had led to physical and behavioural changes. Within our common environment experiment we compared a range of anti-predator behaviours including trap and feeding behaviour and response to predator scent and models. We found evidence for persistent trait changes up to 7 months, the latest time behaviours were tested, after bettongs were moved to the predator-free common environment and isolated from predators. These behaviours include reduced alarm rates, preference for open areas, and responses to predator scent and model stimuli. Additionally, high risk predator cues were more likely to elicit anti-predator responses than passive measures of anti-predator behaviour. Our design shows that predator exposure leads to persistent shifts in some, but not all, anti-predator behaviours. Identifying the proximate basis of anti-predator traits is important to develop successful tools to combat prey naiveté.