Movement patterns of feral predators in an arid environment – implications for control through poison baiting

Abstract

Control of introduced predators is critical to both protection and successful reintroduction of threatened prey species. Efficiency of control is improved if it takes into account habitat use, home range and the activity patterns of the predator. These characteristics were studied in feral cats (Felis catus) and red foxes (Vulpes vulpes) in arid South Australia, and results are used to suggest improvements in control methods. In addition, mortality and movement patterns of cats before and after a poison-baiting event were compared. Thirteen cats and four foxes were successfully fitted with GPS data-logger radio-collars and tracked 4-hourly for several months. High intra-specific variation in cat home-range size was recorded, with 95% minimum convex polygon (MCP) home ranges varying from 0.5 km 2 to 132 km 2 . Cat home-range size was not significantly different from that of foxes, nor was there a significant difference related to sex or age. Cats preferred habitat types that support thicker vegetation cover, including creeklines and sand dunes, whereas foxes preferred sand dunes. Cats used temporary focal points (areas used intensively over short time periods and then vacated) for periods of up to 2 weeks and continually moved throughout their home range. Aerial baiting at a density of 10 baits per km 2 was ineffective for cats because similar high mortality rates were recorded for cats in both baited and unbaited areas. Mortality was highest in young male cats. Long-range movements of up to 45 km in 2 days were recorded in male feral cats and movement into the baited zone occurred within 2 days of baiting. Movement patterns of radio-collared animals and inferred bait detection distances were used to suggest optimum baiting densities of~30 baits per km 2 for feral cats and 5 per km 2 for foxes. Feral cats exhibited much higher intra-specific variation in activity patterns and home-range size than did foxes, rendering them a potentially difficult species to control by a single method. Control of cats and foxes in arid Australia should target habitats with thick vegetation cover and aerial baiting should ideally occur over areas of several thousand square kilometres because of large home ranges and long-range movements increasing the chance of fast reinvasion. The use of temporary focal points suggested that it may take several days or even weeks for a cat to encounter a fixed trap site within their home range, whereas foxes should encounter them more quickly as they move further each day although they have a similar home-range size. Because of high intra-specific variability in activity patterns and home-range size, control of feral cats in inland Australia may be best achieved through a combination of control techniques. * = 95% minimum convex polygon. = 100% minimum convex polygon. A Hawke's Bay female cat home-range size includes cats from both pasture and swamp habitat respectively. Movement patterns of feral predators in an arid environment Wildlife Research 423 424 Wildlife Research K. E. Moseby et al.

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

“…Biologists on SCI document all roadkill that they observe, and they have never recorded any feral cats ever being accidentally killed on SCI roads. The GPS collars deployed in this study were relatively light, weighing approximately one-half as much as collars employed in previous feral cat studies (Moseby et al 2009;Recio et al 2010;Algar et al 2011;Bengsen et al 2012). Perhaps because collars were lighter, cats wearing transmitters during our study, on average, did not experience the weight loss which was documented as a possible collaring impact in previous research (Bengsen et al 2012).…”

“…Perhaps because collars were lighter, cats wearing transmitters during our study, on average, did not experience the weight loss which was documented as a possible collaring impact in previous research (Bengsen et al 2012). In addition, the battery life of these collars combined with our standardized GPS location schedule of 6 per day, allowed the 11 animals to be studied for substantially longer time periods than previous studies of feral cats employing GPS collars (Moseby et al 2009;Recio et al 2010;Algar et al 2011;Bengsen et al 2012), which theoretically produces more robust home-range estimates (Börger et al 2006). The 82% fix rate that we obtained was higher than those of previous feral cat studies (Recio et al 2010;Buckmaster 2012) and was above a conglomerate average 69% fix rate calculated from 35 wildlife research papers (Cain et al 2005).…”

“…Furthermore, quantifying basic ecological parameters, such as spatial use, is important for control and eradication program planning (Luna-Mendoza et al 2011), implementation , and monitoring (Ramsey et al 2011). However, key characteristics of landscape use by invasive species such as feral cats can vary widely among regions and conditions (Moseby et al 2009). …”

Interference competition: odours of an apex predator and conspecifics influence resource acquisition by red foxes

“…After two nights of habituation, we adhered a 12-cm × 12-cm piece of either unscented, conspecific-scented, or predator-scented towel (described below) to the edge of each tray using double-sided tape to simulate scent marking and activity near food resources by dingoes and foxes (Wallach et al 2009). We placed the towel on the side of the tray closest to the path the animal would likely take from the road; in arid environments foxes prefer moving along 'pathways' with sparse vegetation, such as ridges of longitudinal sand dunes or dirt roads (Moseby et al 2009;Mahon et al 1998) and thus we expected them to approach the foraging trays from the direction of sand ridges and roads. For treatments with a predator-or conspecific-scented towel, we then placed a single predator or conspecific scat, respectively, in the pathway zone 20 cm from the foraging tray.…”

First in, first served: uptake of 1080 poison fox baits in south-west Western Australia

“…urban, agricultural, forest, arid;Phillips and Catling 1991;Lucherini and Lovari 1996;Moseby et al 2009b), all of which exert different selection pressures and influences on this invasive species. Information on the movements and habitat use of target species could be applied to improve efficacy of baiting regimes (Moseby et al 2009b); for example, identifying whether the location of bait placement influences the chances of foxes locating and consuming the baits.…”