Melissa Thomas

The use of road underpasses by feral cats (Felis catus) and native wildlife. Context: Underpasses are incorporated into roads to encourage animal movement across fragmented landscapes. However, observations of introduced predators – such as feral cats – has raised speculation that they target underpasses for hunting native species and utilising shelter. Aims: The study examined (1) if feral cats and native wildlife used underpasses, (2) which underpass characteristics were correlated with more animal use, and (3) if underpasses could act as ‘lures’ for targeted cat control. Methods: Located at Alcoa’s two bauxite mines in Western Australia, 64 motion camera traps were deployed across 16 road underpasses over a period of four months. Four cameras were set up at each underpass; one on each end of the underpass, each paired with another camera 30m away in the adjacent bush. Key results: Underpasses were used by native species, including echidna, chuditch, rakali, and mardo to cross beneath roads; quokkas and bandicoots were detected at the edge of underpasses, but rarely entered. Observations of feral pigs and foxes using underpasses to pass beneath roads were also recorded. Additionally, 14 individual cats were identified using underpasses as a thoroughfare; one cat was observed regularly at underpasses approximately 5km apart, and another cat took refuge inside an underpass out of the rain for 49 minutes. Conclusions: While the study provided no direct evidence of predation by feral cats at underpasses to confirm the ‘prey-trap hypothesis’, it also could not be dismissed due to frequent feral cat detections at underpass sites, the regular return of individuals, and extended periods of time spent inside underpasses. The study successfully identified underpasses as potential locations for targeted cat control for more effective management of feral cats for the conservation of Australian biodiversity.