Acoustic deterrents for Red Fox Vulpes vulpes and threatened shorebird clutch survival on sandy beaches

Abstract

Red Foxes Vulpes vulpes are a key driver of low reproductive success in beach-nesting shorebirds such as the Hooded Plover Thinornis cucullatus cucullatus, with lethal fox control curtailed by free-roaming pets and nearby urban dwellings. We tested the efficacy of an ultrasonic deterrent to alter fox behaviour and improve clutch survival. A test of the device on mock clutches demonstrated no apparent negative effect on clutch survival so testing occurred on real clutches. The deterrent evoked responses from foxes. Assemblages of species visiting real clutches differed between treatment and control sites, such that foxes tended to visit control clutches more frequently than those with the acoustic deterrent; rates of fox visitation did not differ yet featured low statistical power. The acoustic device did not confer any large benefit in terms of improved clutch survival, although low statistical power precluded us from assessing whether smaller effects occurred. This study suggests that additional aversive stimuli are likely required to deter fox take of real plover eggs.

Keywords

• Aversion
• Avoidance
• Hooded plover
• Threatened species conservation
• Ultrasonic deterrent