Is anti-predator behaviour in Tasmanian eastern quolls (Dasyurus viverrinus) effective against introduced predators?

Abstract

Exotic predators, particularly red foxes (Vulpes vulpes) and feral cats (Felis catus), have been implicated in the declines and extinctions of many Australian mammals and a recent incursion of foxes into Tasmania has therefore caused great concern. We tested the behavioural responses of eastern quolls (Dasyurus viverrinus) to acoustic cues of native (masked owl (Tyto novaehollandiae castanops) and Tasmanian devil (Sarcophilus laniarius)) and non-native (fox and cat) predators and to non-predators (cow (Bos taurus) and control noise). Juvenile quolls treated fox vocalisations like those of cows (as measured by an increase in movement), in contrast to their responses (a decrease in movement) to sympatric predators. Cats are probably a lesser threat to eastern quolls than native predators or foxes, their impact probably being greatest on the juveniles. Juvenile quolls, but not adults, showed similar responses to cat vocalisations as they did to owls and devils. Adult quolls responded differently from juveniles to owls and devils, by increasing vigilance. This is consistent with the smaller body size, inexperience and the presumed greater vulnerability of juveniles to predation. The lack of appropriate anti-predator responses to foxes suggests that eastern quolls would be vulnerable to predation by foxes in Tasmania.