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

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 immi- grating predators take time to learn to locate prey cues in their new environment. We urge re- searchers to investigate fine-scale drivers of movement patterns as this information is likely to be critical for long term management of predator species.K.E. Moseby, H.M. McGrego

Factors affecting success of conservation translocations of terrestrial vertebrates: a global systematic review

Translocation—moving individuals for release in different locations—is among the most important conservation interventions for increasing or re-establishing populations of threatened species. However, translocations often fail. To improve their effectiveness, we need to understand the features that distinguish successful from failed translocations. We assembled and analysed a global database of translocations of terrestrial vertebrates (n = 514) to assess the effects of various design features and extrinsic factors on success. We analysed outcomes using standardised metrics: a categorical success/failure classification; and population growth rate. Probability of categorical success and population growth rate increased with the total number of individuals released but with diminishing returns above about 20–50 individuals. Positive outcomes—categorical success and high population growth—were less likely for translocations in Oceania, possibly because invasive species are a major threat in this region and are difficult to control at translocation sites. Rates of categorical success and population growth were higher in Europe and North America than elsewhere, suggesting the key role of context in positive translocation outcomes. Categorical success has increased throughout the 20th century, but that increase may have plateaued at about 75% since about 1990. Our results suggest there is potential for further increase in the success of conservation translocations. This could be best achieved by greater investment in individual projects, as indicated by total number of animals released, which has not increased over time.Shane D. Morris, Barry W. Brook, Katherine E. Moseby, Christopher N. Johnso

Long-distance movements of feral cats in semi-arid South Australia and implications for conservation management

Movements that extend beyond the usual space use of an animal have been documented in a range of species and are particularly prevalent in arid areas. We present long-distance movement data on five feral cats (Felis catus) GPS/VHF-collared during two different research projects in arid and semi-arid Australia. We compare these movements with data from other feral cat studies. Over a study period of three months in the Ikara-Flinders Ranges National Park, 4 out of 19 collared cats moved to sites that were 31, 41, 53 and 86 km away. Three of the cats were males, one female; their weight was between 2.1 and 4.1 kg. Two of the cats returned to the area of capture after three and six weeks. During the other study at Arid Recovery, one collared male cat (2.5 kg) was relocated after two years at a distance of 369 km from the area of collar deployment to the relocation area. The movements occurred following three years of record low rainfall. Our results build on the knowledge base of long-distance movements of feral cats reported at arid study sites and support the assertion that landscape-scale cat control programs in arid and semi-arid areas need to be of a sufficiently large scale to avoid rapid reinvasion and to effectively reduce cat density. Locally, cat control strategies need to be adjusted to improve coverage of areas highly used by cats to increase the efficiency of control operations.Jeroen Jansen, Hugh McGregor, Geoff Axford, Abbey T. Dean, Sebastien Comte, Chris N. Johnson, Katherine E. Moseby, Robert Brandle, David E. Peacock, and Menna E. Jone

Harnessing natural selection to tackle the problem of prey naivete

Many populations are threatened or endangered because of excessive predation resulting from individuals’ inability to recognize, avoid, or escape alien predators. Such prey na€ıvete is often attributed to the absence of prior experience and co-evolution between native prey and introduced predators. Many reintroduction programs focus on reducing predation rate by excluding introduced predators, a focus which ignores, and indeed exacerbates, the problem of prey na€ıvete. We argue for a new paradigm in reintroduction biology that expands the focus from predator control to kick-starting learning and evolutionary processes between alien predators and reintroduced prey. By exposing reintroduced prey to carefully controlled levels of alien predators, in situ predation could enhance reintroduction success by facilitating acquisition of learned antipredator responses and through natural selection for appropriate antipredator traits. This in situ predator exposure should be viewed as a long-term process but is likely to be the most efficient and expedient way to improve prey responses and assist in broadscale recovery of threatened species.Katherine E. Moseby, Daniel T. Blumstein, Mike Letni

In situ predator conditioning of naive prey prior to reintroduction

Many translocations and introductions to recover threatened populations fail because predators kill prey soon after release; a problem exacerbated for predator-naive prey. While pre-release training has been shown to work in some situations, it is time consuming and relies on using inferred predator cues and treating small groups. We review a relatively new and very promising management tool: in situ, pre-release predator conditioning. Here, the goal is to allow prey in large enclosures to live with low densities of predators to accelerate selection for antipredator traits (in an evolutionary sense) or provide prey essential experience with predators that they will later encounter. We review the published results of a large-scale, controlled experiment where we have permitted burrowing bettongs (Bettongia lesueur) and greater bilblies (Macrotis lagotis) to live with low densities of feral cats (Felis catus), a species implicated in their widespread decline and localized extinction. We found that both species could persist with cats, suggesting that future work should define coexistence thresholds-which will require knowledge of prey behaviour as well as the structure of the ecological community. Compared to control populations, predator-naive prey exposed to cats has a suite of morphological and behavioural responses that seemingly have increased their antipredator abilities. Results suggest that predator-conditioned bilbies survive better when released into a large enclosure with an established cat population; future work will determine whether this increased survival extends to the wild. This article is part of the theme issue 'Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.Daniel T. Blumstein, Mike Letnic and Katherine E. Moseb

Understanding dispersal patterns can inform future translocation strategies: A case study of the threatened greater stick‐nest rat (Leporillus conditor)

Dispersal behaviour and sociality are significant factors influencing survival at both the individual and population levels. In translocation and breeding programmes, social structure and sex-biased philopatry and dispersal should be considered in order to maximise population viability and conservation outcomes. Here, we use the greater stick-nest rat (Leporillus conditor), a native Australian rodent, as a case study to understand how knowledge of social structure and dispersal can inform conservation and translocation programmes. We combine high-throughput DNA sequencing with field trapping data from a translocated population of greater stick-nest rats at Arid Recovery Reserve, South Australia, to provide the first empirical evidence of female philopatry and male-biased dispersal in this species. Males were found to disperse, on average, 1.5 km from the natal nest, while females typically did not disperse beyond 500 m. Further, recapture data showed that females demonstrated a higher degree of nest fidelity than males over time. Based on these findings, we make two key recommendations for future translocations of the species. Firstly, founders should be harvested in small groups at adjacent nest sites with groups separated by a minimum of 1.5 km allowing family group structure to be retained during translocation while simultaneously maximising genetic diversity. Secondly, translocated individuals should be released in family cohorts into patches of optimal habitat that contain adequate shelter substrates interspersed over short distances (~300–500 m, the maximum dispersal distance of females found in this study), thereby facilitating nest establishment and maintenance of family groups. The results of this study have implications for conservation and reintroduction biology as a whole; we highlight the importance of considering spatial genetic structure during all stages of translocations to improve outcomes, and the value of combining genetic and field data to better understand species’ social and spatial preferences.Isabelle R. Onley, Jeremy J. Austin, Kieren J. Mitchell and Katherine E. Moseb

Searching for an effective pre-release screening tool for translocations: can trap temperament predict behaviour and survival in the wild?

Individuals often respond to threatening situations in consistently different ways and these differences may predict later translocation success. Thus, the ability to easily identify these differences prior to translocation may assist in improving conservation outcomes. We asked whether burrowing bettongs (Bettongia lesueur), a marsupial species that has undergone significant decline since the introduction of exotic predators to Australia, responded in consistently different ways to capture in traps, and if so, whether this was related to anti-predator behaviour, ranging behaviour and survival following translocation. Behavioural responses of 40 bettongs were measured and included response to removal from traps (trap docility), latency to leave a trap or bag and escape behaviour upon release. We used flight initiation distance to measure escape behaviour, and distance moved from diurnal refuges during nocturnal foraging to measure ranging behaviour. Survival was measured through radiotracking after release. Behaviours scored during removal from a trap were consistent and repeatable, and formed a behavioural syndrome with anti-predator and ranging behaviour. Less docile bettongs foraged closer to refuges and had longer flight initiation distances. Less docile bettongs were also more likely to survive after release, although the sample size of mortalities was small. Our results suggest that behaviours scored during trapping could be a useful metric for pre-release screening in translocation programs to enhance the chances of individual survival post-release.R.S. West, D.T. Blumstein, M. Letnic, K.E. Moseb

Reversing the effects of evolutionary prey naiveté through controlled predator exposure

1. Inappropriate anti‐predator responses (naiveté) towards introduced predators is a key factor contributing to the extinction and endangerment of prey species worldwide and the failure of wildlife reintroductions. Here, we test the idea that success of reintroduction can be improved by exposing a predator naïve prey species to introduced predators under controlled conditions (in situ predation) prior to reintroduction, such that prey adopt increased wary behaviours to aid in survival. 2. We exposed a population of a naïve marsupial, the greater bilby (Macrotis lagotis), to a controlled number of introduced predators (feral cats, Felis catus) for 2 years within a large fenced paddock and then compared the pre‐release behaviour and post‐translocation survival of predator‐exposed and predator‐naïve bilbies over 40 days. 3. Behavioural assays conducted in a small pen prior to reintroduction suggested that predator‐exposed bilbies were warier as they spent less time moving and more time in cover than predator naïve bilbies. 4. After translocation, predator‐exposed bilbies were more likely to survive to 40 days and were less likely to be preyed upon by cats than predator‐free bilbies. 5. Synthesis and applications. Naiveté towards predators is a major problem thwarting successful reintroductions world‐wide. Our study demonstrates that exposure to predators under controlled conditions can increase survival of reintroduced prey and is a promising approach to overcome the problem of naiveté towards introduced predators and the global problem of prey naiveté. Future conservation of naïve prey species may depend on such training methods prior to releasing into areas where predators are present.Alexandra K. Ross, Mike Letnic, Daniel T. Blumstein, Katherine E. Moseb

Predator exposure enhances the escape behaviour of a small marsupial, the burrowing bettong

Predator-protected populations of threatened fauna are important for species conservation, although these animals can quickly become predator naïve and can lack appropriate antipredator behaviour to enable them to persist once released. Controlled predator exposure can improve predator recognition and encourage avoidance behaviour, but little is known about the escape responses or fleeing behaviour of prey species. We compared the escape behaviour of a small marsupial, the burrowing bettong, Bettongia lesueur, between two fenced populations: one that had been purposely exposed to feral cats, Felis catus, while the other had been maintained without exotic predators. To quantify escape behaviour, bettongs were trapped and released into a temporary runway and a threatening stimulus was introduced to encourage them to flee. Measures relating to reactivity (escape initiation), escape speed and flight path (protean characteristics: agility, path irregularity and straightness) were recorded from video footage. Cat-exposed bettongs were significantly heavier than those from the cat-naïve population. We found a significant effect of the interaction of treatment (‘cat-exposed’ or ‘cat-naïve’) and body mass on overall escape behaviour. These differences were attributed to increased reactivity and escape speed in cat-exposed bettongs, but not protean characteristics of their flight path. Cat-exposed bettongs fled at an intensity where body size affected their escape performance (larger animals performed longer bounds and achieved faster speeds), while this body size effect was not evident for cat-naïve animals. This result suggests the cat-naïve animals were not as motivated to flee. Introducing low levels of predation pressure can successfully promote the development of antipredator behaviour through selection and/or individual learning, including a heightened escape response. Controlled predator exposure may be able to address some types of prey naïvety and lead to increased survival outside predator-free sanctuaries