Spatial ecology of invasive feral cats on San Clemente Island: implications for control and management

Abstract

Feral cats, Felis catus, inhabiting San Clemente Island, California, are both predators and competitors of multiple sympatric endemic species. To improve our understanding and management of these invasive predators, we used GPS-equipped radiocollars to track 11 (6F:5M) cats for a total of 3,108 days, resulting in 15,419 GPS locations. Average 100% minimum convex polygon, 95% kernel density, and 50% kernel density estimates were 229, 132, and 33 ha, respectively. The point estimate for average male home-range size was larger than the average for females, but there was substantial variation among individuals of both sexes. Overlap indices indicated similar usage areas during nocturnal and diurnal time periods. Sample size limited our ability to definitively detect habitat preference, but data suggested areas within 50 m of roads were avoided, and that thicker land cover was preferred over open grasslands. Three test collars deployed within active cat home ranges indicated GPS locations were precise, with 96% of locations having < 10-m error estimates, and that horizontal dilution of precision indices were not useful in screening data. Our results describe feral cat spatial ecology on a semiarid island and can be used to inform population estimation, control, and mitigation programs.

Laying low: Rugged lowland rainforest preferred by feral cats in the Australian Wet Tropics

“…Roads may accelerate the spread of invasive vertebrate predators by allowing species to move efficiently across landscapes and colonize areas that they would otherwise take longer to reach (Hradsky et al, 2017; Raiter et al, 2018). Studies in Australia have generally found feral cats preferentially travel along linear features like roads but see Bridges et al (2015) (Wang & Fisher, 2012; Wysong, Hradsky, et al, 2020; Wysong, Iacona, et al, 2020). Within the AWT there is an extensive network of roads bisecting otherwise intact habitats, and feral cats may have been using them undetected for decades.…”

Laying low: Rugged lowland rainforest preferred by feral cats in the Australian Wet Tropics.

“…Roads may accelerate the spread of invasive vertebrate predators by allowing species to move efficiently across landscapes and colonize areas that they would otherwise take longer to reach (Hradsky et al, 2017;Raiter et al, 2018). Studies in Australia have generally found feral cats preferentially travel along linear features like roads but see Bridges et al (2015) (Wang & Fisher, 2012;Wysong, Hradsky, et al, 2020;. Within the AWT there is an extensive network of roads bisecting otherwise intact habitats, and feral cats may have been using them undetected for decades.…”

Laying low: Rugged lowland rainforest preferred by feral cats in the Australian Wet Tropics.

“…Roads may accelerate the spread of invasive vertebrate predators by allowing species to move efficiently across landscapes and colonize areas that they would otherwise take longer to reach (Hradsky et al, 2017;Raiter et al, 2018). Studies in Australia have generally found feral cats preferentially travel along linear features like roads but see Bridges et al (2015) (Wang & Fisher, 2012;Wysong, Hradsky, et al, 2020;. Within the AWT there is an extensive network of roads bisecting otherwise intact habitats, and feral cats may have been using them undetected for decades.…”