An Evaluation of Systematic Versus Strategically-Placed Camera Traps for Monitoring Feral Cats in New Zealand

We deploy camera traps to monitor feral cat (Felis catus) populations at two pastoral sites in Hawke’s Bay, North Island, New Zealand. At Site 1, cameras are deployed at pre-determined GPS points on a 500-m grid, and at Site 2, cameras are strategically deployed with a bias towards forest and forest margin habitat where possible. A portion of cameras are also deployed in open farmland habitat and mixed scrub. We then use the abundance-induced heterogeneity Royle–Nichols model to estimate mean animal abundance and detection probabilities for cameras in each habitat type. Model selection suggests that only cat abundance varies by habitat type. Mean cat abundance is highest at forest margin cameras for both deployment methods (3 cats [95% CI 1.9–4.5] Site 1, and 1.7 cats [95% CI 1.2–2.4] Site 2) but not substantially higher than in forest habitats (1.7 cats [95% CI 0.8–3.6] Site 1, and 1.5 cats [95% CI 1.1–2.0] Site 2). Model selection shows detection probabilities do not vary substantially by habitat (although they are also higher for cameras in forest margins and forest habitats) and are similar between sites (8.6% [95% CI 5.4–13.4] Site 1, and 8.3% [5.8–11.9] Site 2). Cat detections by camera traps are higher when placed in forests and forest margins; thus, strategic placement may be preferable when monitoring feral cats in a pastoral landscape.

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On the right track: placement of camera traps on roads improves detection of predators and shows non-target impacts of feral cat baiting

Wildlife Research ◽

10.1071/wr19175 ◽

2020 ◽

Vol 47 (8) ◽

pp. 557 ◽

Cited By ~ 1

Author(s):

Michael L. Wysong ◽

Gwenllian D. Iacona ◽

Leonie E. Valentine ◽

Keith Morris ◽

Euan G. Ritchie

Keyword(s):

Survey Design ◽

Camera Traps ◽

Apex Predator ◽

Target Species ◽

Ecological Consequences ◽

Large Herbivores ◽

Feral Cat ◽

Feral Cats ◽

Detection Probabilities ◽

Poison Baiting

Abstract ContextTo understand the ecological consequences of predator management, reliable and accurate methods are needed to survey and detect predators and the species with which they interact. Recently, poison baits have been developed specifically for lethal and broad-scale control of feral cats in Australia. However, the potential non-target effects of these baits on other predators, including native apex predators (dingoes), and, in turn, cascading effects on lower trophic levels (large herbivores), are poorly understood. AimsWe examined the effect that variation in camera trapping-survey design has on detecting dingoes, feral cats and macropodids, and how different habitat types affect species occurrences. We then examined how a feral cat poison baiting event influences the occupancy of these sympatric species. MethodsWe deployed 80 remotely triggered camera traps over the 2410-km2 Matuwa Indigenous Protected Area, in the semiarid rangelands of Western Australia, and used single-season site-occupancy models to calculate detection probabilities and occupancy for our target species before and after baiting. Key resultsCameras placed on roads were ~60 times more likely to detect dingoes and feral cats than were off-road cameras, whereas audio lures designed to attract feral cats had only a slight positive effect on detection for all target species. Habitat was a significant factor affecting the occupancy of dingoes and macropodids, but not feral cats, with both species being positively associated with open woodlands. Poison baiting to control feral cats did not significantly reduce their occupancy but did so for dingoes, whereas macropodid occupancy increased following baiting and reduced dingo occupancy. ConclusionsCamera traps on roads greatly increase the detection probabilities for predators, whereas audio lures appear to add little or no value to increasing detection for any of the species we targeted. Poison baiting of an invasive mesopredator appeared to negatively affect a non-target, native apex predator, and, in turn, may have resulted in increased activity of large herbivores. ImplicationsManagement and monitoring of predators must pay careful attention to survey design, and lethal control of invasive mesopredators should be approached cautiously so as to avoid potential unintended negative ecological consequences (apex-predator suppression and herbivore release).

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Evaluation of risks for two native mammal species from feral cat baiting in monsoonal tropical northern Australia

Wildlife Research ◽

10.1071/wr17171 ◽

2018 ◽

Vol 45 (6) ◽

pp. 518 ◽

Cited By ~ 3

Author(s):

Jaime Heiniger ◽

Skye F. Cameron ◽

Graeme Gillespie

Keyword(s):

Rhodamine B ◽

Native Species ◽

Field Trials ◽

Camera Traps ◽

Northern Australia ◽

Target Species ◽

Mammal Species ◽

Feral Cat ◽

Feral Cats ◽

Dry Tropics

Context Feral cats are a significant threat to native wildlife and broad-scale control is required to reduce their impacts. Two toxic baits developed for feral cats, Curiosity® and Hisstory®, have been designed to reduce the risk of baiting to certain non-target species. These baits involve encapsulating the toxin within a hard-shelled delivery vehicle (HSDV) and placing it within a meat attractant. Native animals that chew their food more thoroughly are predicted to avoid poisoning by eating around the HSDV. This prediction has not been tested on wild native mammals in the monsoonal wet–dry tropics of the Northern Territory. Aim The aim of this research was to determine whether northern quolls (Dasyurus hallucatus) and northern brown bandicoots (Isoodon macrourus) would take feral cat baits and ingest the HSDV under natural conditions on Groote Eylandt. Methods We hand-deployed 120 non-toxic baits with a HSDV that contained a biomarker, Rhodamine B, which stains animal whiskers when ingested. The species responsible for bait removal was determined with camera traps, and HSDV ingestion was measured by evaluating Rhodamine B in whiskers removed from animals trapped after baiting. Key results During field trials, 95% of baits were removed within 5 days. Using camera-trap images, we identified the species responsible for taking baits on 65 occasions. All 65 confirmed takes were by native species, with northern quolls taking 42 baits and northern brown bandicoots taking 17. No quolls and only one bandicoot ingested the HSDV. Conclusion The use of the HSDV reduces the potential for quolls and bandicoots to ingest a toxin when they consume feral cat baits. However, high bait uptake by non-target species may reduce the efficacy of cat baiting in some areas. Implications The present study highlighted that in the monsoonal wet–dry tropics, encapsulated baits are likely to minimise poisoning risk to certain native species that would otherwise eat meat baits. However, further research may be required to evaluate risks to other non-target species. Given the threat to biodiversity from feral cats, we see it as critical to continue testing Hisstory® and Curiosity® in live-baiting trials in northern Australia.

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Does aerial baiting for controlling feral cats in a heterogeneous landscape confer benefits to a threatened native meso-predator?

PLoS ONE ◽

10.1371/journal.pone.0251304 ◽

2021 ◽

Vol 16 (5) ◽

pp. e0251304

Author(s):

Russell Palmer ◽

Hannah Anderson ◽

Brooke Richards ◽

Michael D. Craig ◽

Lesley Gibson

Keyword(s):

Native Species ◽

Activity Patterns ◽

Camera Traps ◽

Feral Cat ◽

Feral Cats ◽

Gps Collars ◽

Control Programs ◽

Treatment Site ◽

National Priority ◽

Positive Effect

Introduced mammalian predators can have devastating impacts on recipient ecosystems and disrupt native predator–prey relationships. Feral cats (Felis catus) have been implicated in the decline and extinction of many Australian native species and developing effective and affordable methods to control them is a national priority. While there has been considerable progress in the lethal control of feral cats, effective management at landscape scales has proved challenging. Justification of the allocation of resources to feral cat control programs requires demonstration of the conservation benefit baiting provides to native species susceptible to cat predation. Here, we examined the effectiveness of a landscape-scale Eradicat® baiting program to protect threatened northern quolls (Dasyurus hallucatus) from feral cat predation in a heterogeneous rocky landscape in the Pilbara region of Western Australia. We used camera traps and GPS collars fitted to feral cats to monitor changes in activity patterns of feral cats and northern quolls at a baited treatment site and unbaited reference site over four years. Feral cat populations appeared to be naturally sparse in our study area, and camera trap monitoring showed no significant effect of baiting on cat detections. However, mortality rates of collared feral cats ranged from 18–33% after baiting, indicating that the program was reducing cat numbers. Our study demonstrated that feral cat baiting had a positive effect on northern quoll populations, with evidence of range expansion at the treatment site. We suggest that the rugged rocky habitat preferred by northern quolls in the Pilbara buffered them to some extent from feral cat predation, and baiting was sufficient to demonstrate a positive effect in this relatively short-term project. A more strategic approach to feral cat management is likely to be required in the longer-term to maximise the efficacy of control programs and thereby improve the conservation outlook for susceptible threatened fauna.

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Pre-eradication assessment of feral cat density and population size across Kangaroo Island, South Australia

Wildlife Research ◽

10.1071/wr19137 ◽

2020 ◽

Vol 47 (8) ◽

pp. 669

Author(s):

Rosemary Hohnen ◽

Karleah Berris ◽

Pat Hodgens ◽

Josh Mulvaney ◽

Brenton Florence ◽

...

Keyword(s):

Habitat Type ◽

South Australia ◽

Habitat Types ◽

Feral Cat ◽

Feral Cats ◽

Order Of Magnitude ◽

Capture Recapture ◽

Remote Camera ◽

Camera Arrays ◽

The Relationship

Abstract Context Feral cats (Felis catus) are a significant threat to wildlife in Australia and globally. In Australia, densities of feral cats vary across the continent and also between the mainland and offshore islands. Densities on small islands may be at least an order of magnitude higher than those in adjacent mainland areas. To provide cat-free havens for biodiversity, cat-control and eradication programs are increasingly occurring on Australian offshore islands. However, planning such eradications is difficult, particularly on large islands where cat densities could vary considerably. Aims In the present study, we examined how feral cat densities vary among three habitats on Kangaroo Island, a large Australian offshore island for which feral cat eradication is planned. Methods Densities were compared among the following three broad habitat types: forest, forest–farmland boundaries and farmland. To detect cats, three remote-camera arrays were deployed in each habitat type, and density around each array was calculated using a spatially explicit capture–recapture framework. Key results The average feral cat density on Kangaroo Island (0.37 cats km−2) was slightly higher than that on the Australian mainland. Densities varied from 0.06 to 3.27 cats km−2 and were inconsistent within broad habitat types. Densities were highest on farms that had a high availability of macropod and sheep carcasses. The relationship between cat density and the proportion of cleared land in the surrounding area was weak. The total feral cat population of Kangaroo Island was estimated at 1629±661 (mean±s.e.) individuals. Conclusions Cat densities on Kangaroo Island are highly variable and may be locally affected by factors such as prey and carrion availability. Implications For cat eradication to be successful, resources must be sufficient to control at least the average cat density (0.37 cats km−2), with additional effort around areas of high carcass availability (where cats are likely to be at a higher density) potentially also being required.

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Two Methods of Monitoring Cats at a Landscape-Scale

Animals ◽

10.3390/ani11123562 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3562

Author(s):

Cheryl A. Lohr ◽

Kristen Nilsson ◽

Ashleigh Johnson ◽

Neil Hamilton ◽

Mike Onus ◽

...

Keyword(s):

Protected Area ◽

Landscape Scale ◽

Camera Traps ◽

Feral Cat ◽

Feral Cats ◽

The Cost ◽

Track Counts

Feral cats are difficult to manage and harder to monitor. We analysed the cost and the efficacy of monitoring the pre- and post-bait abundance of feral cats via camera-traps or track counts using four years of data from the Matuwa Indigenous Protected Area. Additionally, we report on the recovery of the feral cat population and the efficacy of subsequent Eradicat® aerial baiting programs following 12 months of intensive feral cat control in 2019. Significantly fewer cats were captured in 2020 (n = 8) compared to 2019 (n = 126). Pre-baiting surveys for 2020 and 2021 suggested that the population of feral cats on Matuwa was very low, at 5.5 and 4.4 cats/100 km, respectively, which is well below our target threshold of 10 cats/100 km. Post-baiting surveys then recorded 3.6 and 3.0 cats/100 km, respectively, which still equates to a 35% and 32% reduction in cat activity. Track counts recorded significantly more feral cats than camera traps and were cheaper to implement. We recommend that at least two methods of monitoring cats be implemented to prevent erroneous conclusions.

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Feral cat abundance, density and activity in tropical island rainforests

Wildlife Research ◽

10.1071/wr19205 ◽

2020 ◽

Vol 47 (8) ◽

pp. 660

Author(s):

Tyrone H. Lavery ◽

Masaafi Alabai ◽

Piokera Holland ◽

Cornelius Qaqara ◽

Nelson Vatohi

Keyword(s):

Camera Traps ◽

Western Pacific ◽

Tropical Islands ◽

The South ◽

Mammal Species ◽

Bird Abundance ◽

Tropical Island ◽

Study Region ◽

Feral Cat ◽

Feral Cats

Abstract ContextIntroduced predators, especially cats, are a major cause of extinction globally. Accordingly, an extensive body of literature has focussed on the ecology and management of feral cats in continental and island systems alike. However, geographic and climatic gaps remain, with few studies focusing on rainforests or tropical islands of the south-western Pacific. AimsWe aimed to estimate cat densities and elucidate activity patterns of cats and sympatric birds and mammals in tropical island rainforests. We hypothesised that cat activity would be most influenced by the activity of introduced rodents and ground-dwelling birds that are predominant prey on islands. MethodsWe used camera traps to detect feral cats, pigs, rodents and birds on four tropical islands in the south-western Pacific. We used spatial capture–recapture models to estimate the abundance and density of feral cats. Relative abundance indices, and temporal overlaps in activity were calculated for feral cats, pigs, rodents, and birds. We used a generalised linear model to test for the influence of pig, rodent, and bird abundance on feral cat abundance. Key resultsThe species most commonly detected by our camera traps was feral cat, with estimated densities between 0.31 and 2.65 individuals km−2. Pigs and introduced rodents were the second- and third-most commonly detected fauna respectively. Cat activity was bimodal, with peaks in the hours before dawn and after dusk. Cat abundance varied with site and the abundance of rodents. ConclusionsFeral cats are abundant in the tropical rainforests of our study islands, where one bird and two mammal species are now presumed extinct. Introduced rodents possibly amplify the abundance and impacts of feral cats at our sites. Peak cat activity following dusk did not clearly overlap with other species detected by our camera traps. We postulate cats may be partly focussed on hunting frogs during this period. ImplicationsCats are likely to be a major threat to the highly endemic fauna of our study region. Management of feral cats will benefit from further consideration of introduced prey such as rodents, and their role in hyperpredation. Island archipelagos offer suitable opportunities to experimentally test predator–prey dynamics involving feral cats.

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Multiple Methods of Monitoring Cats at a Landscape-scale

10.20944/preprints202111.0258.v1 ◽

2021 ◽

Author(s):

Cheryl Lohr ◽

Kristen Nilsson ◽

Ashleigh Johnson ◽

Neil Hamilton ◽

Mike Onus ◽

...

Keyword(s):

Protected Area ◽

Landscape Scale ◽

Camera Traps ◽

Multiple Methods ◽

Feral Cat ◽

Feral Cats ◽

Cost Efficacy ◽

The Cost ◽

Track Counts

Feral cats are both difficult to manage and harder to monitor. We analysed the cost-efficacy of monitoring the pre- and post-bait abundance of feral cats via camera-traps or track counts using four years of data from the Matuwa Indigenous protected Area. Additionally, we report on the recovery of the feral cat population and the efficacy of subsequent Eradicat® aerial baiting programs following 12 months of intensive feral cat control in 2019 that consisted of aerial baiting and leg-hold trapping. Significantly fewer cats were captured in 2020 (n = 8) compared to 2019 (n = 126). Pre-baiting surveys for 2020 and 2021 suggested that the population of feral cats on Matuwa was very low, at 5.5 and 4.4 cats/100 km respectively, which is well below our target threshold of 10 cats/100 km. Post-baiting surveys then recorded 3.6 and 3.0 cats/100 km respectively, which still equates to a 35% and 32% reduction in cat activity. Track counts recorded significantly more feral cats than camera traps and were cheaper to implement. We recommend that at least two methods of monitoring cats be implemented to prevent erroneous conclusions.

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Camera trap flash-type does not influence the behaviour of feral cats (Felis catus)

Australian Mammalogy ◽

10.1071/am18056 ◽

2020 ◽

Vol 42 (2) ◽

pp. 220 ◽

Cited By ~ 1

Author(s):

Patrick L. Taggart ◽

David E. Peacock ◽

Bronwyn A. Fancourt

Keyword(s):

Camera Trap ◽

Behavioural Response ◽

Felis Catus ◽

Camera Traps ◽

Feral Cat ◽

Feral Cats ◽

Behavioural Responses

Camera traps are now the most commonly used technique for indexing feral cat (Felis catus) and predator populations. Camera flash-type has been suggested to influence an animal's behaviour and their redetection by similar cameras, with white-flash cameras being shown to reduce the probability of redetecting some species. We investigated the influence of camera flash-type on the behaviour of feral cats by categorising their behavioural response to white-flash and infrared-flash cameras and assessing the frequency with which individual cats were redetected by the same white-flash camera or a different white-flash camera at the same site following their initial detection. We found no evidence that flash type had any influence on the cats’ observed behavioural responses towards cameras, or that cats captured by white-flash cameras avoided redetection. Our findings suggest that white-flash cameras are suitable for the detection and redetection of cats, and provide better-quality images from which to identify individual cats.

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Estimating and indexing feral cat population abundances using camera traps

Wildlife Research ◽

10.1071/wr11134 ◽

2011 ◽

Vol 38 (8) ◽

pp. 732 ◽

Cited By ~ 51

Author(s):

Andrew Bengsen ◽

John Butler ◽

Pip Masters

Keyword(s):

Relative Abundance ◽

Population Decline ◽

Camera Traps ◽

Camera Trapping ◽

Gps Tracking ◽

Range Data ◽

Population Abundance ◽

Feral Cat ◽

Feral Cats ◽

Infrared Cameras

Context The ability to monitor changes in population abundance is critical to the success of pest animal management and research programs. Feral cats (Felis catus) are an important pest animal, but current monitoring techniques have limited sensitivity or are limited in use to particular circumstances or habitats. Recent advances in camera-trapping methods provide the potential to identify individual feral cats, and to use this information to estimate population abundances using capture–mark–recapture (CMR) methods. Aims Here, we use a manipulative study to test whether camera-trapping and CMR methods can be used to estimate feral cat abundances. Methods We established a grid of infrared cameras and lure stations over three pastoral properties on Kangaroo Island, Australia, for 15 days. We then reduced the population abundance with an intensive trapping program and repeated the camera survey. We estimated population abundances using robust design CMR models, and converted abundance estimates to densities using home-range data from GPS tracking. We also calculated relative abundance indices from the same data. Key results The CMR methods produced credible estimates of the change in population abundance, with useful confidence intervals, showing a statistically identifiable population decline from at least 0.7 cats km–2 before trapping down to 0.4 cats km–2 after trapping. The indexing method also showed a statistically identifiable decrease in abundance. Conclusions Camera-trapping and CMR methods can provide a useful method for monitoring changes in the absolute abundance of feral cat populations. Camera-trap data may also be used to produce indices of relative abundance when the assumptions of CMR models cannot be met. Implications These methods are widely applicable. The ability to reliably estimate feral cat abundances allows for more effective management than is generally available.

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An Adaptive Strategy for Reducing Feral Cat Predation on Endangered Hawaiian Birds

Pacific Conservation Biology ◽

10.1071/pc090056 ◽

2009 ◽

Vol 15 (1) ◽

pp. 56 ◽

Cited By ~ 5

Author(s):

Steven C. Hess ◽

Paul C. Banko ◽

Heidi Hansen

Keyword(s):

Linear Models ◽

Habitat Type ◽

Adaptive Strategy ◽

The West ◽

Feral Cat ◽

Feral Cats ◽

Ranking Criteria ◽

Control Programmes ◽

Herpestes Auropunctatus ◽

History Of

Despite the long history of Feral Cats Felis catus in Hawai?i, there has been little research to provide strategies to improve control programmes and reduce depredation on endangered species. Our objective was to develop a predictive model to determine how landscape features on Mauna Kea, such as habitat, elevation, and proximity to roads, may affect the number of Feral Cats captured at each trap. We used log-link generalized linear models and QAICc model ranking criteria to determine the effect of these factors. We found that the number of cats captured per trap was related to effort, habitat type, and whether traps were located on the West or North Slope of Mauna Kea. We recommend an adaptive management strategy to minimize trapping interference by non-target Small Indian Mongoose Herpestes auropunctatus with toxicants, to focus trapping efforts in Mamane Sophora chrysophylla habitat on the West slope of Mauna Kea, and to cluster traps near others that have previously captured multiple cats.

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