Feral cats use fine scale prey cues and microhabitat patches of dense vegetation when hunting prey in arid Australia

Abstract

Introduced predators are one of the leading causes of decline in island vertebrates. Understanding how they hunt and kill threatened prey can help improve management activities. Although broadscale features are known to influence predator movement patterns, factors influencing fine scale movement are often overlooked. In particular, the influence of prey cues and microhabitat features has received little attention despite predators spending considerable time hunting prey using a range of visual, olfactory and auditory cues. Using feral cats as a case study, we utilised video and GPS collars combined with ground-truthing to determine if predators use fine-scale prey cues or microhabitat features to hunt in an arid environment. Feral cat activity was comprised of continuous traverses interspersed with periods of stationary activity (GPS clusters) generally less than 40 min in duration. Video collars confirmed that these clusters included the majority of stalk and pounce hunting bouts. Stationary activity was significantly focussed on prominent prey cues such as burrows, foraging digs or warrens of mammalian prey including both exotic (rabbits) and threatened native species (rodents, bilbies and bettongs). Evidence of prey kills was higher at cluster sites. Cats spent significantly more time at microsites with high vegetation cover including single shrubs and trees, suggesting that they use prominent prey cues and patches of thick cover to increase their probability of encountering prey and/or to conceal themselves during hunting or feeding activity. Results suggest prey species with conspicuous cues are at higher risk of predation and this vulnerability could increase over time as resident cats learn to identify the location of prey cues within their home range. Conversely, removing resident knowledgeable predators may reduce predation rates if immigrating predators take time to learn to locate prey cues in their new environment. We urge researchers to investigate fine-scale drivers of movement patterns as this information is likely to be critical for long term management of predator species.