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Paton AJ, Brook BW, Buettel JC. A non-invasive approach to measuring body dimensions of wildlife with camera traps: A felid field trial. Ecol Evol 2024; 14:e11612. [PMID: 38952652 PMCID: PMC11216788 DOI: 10.1002/ece3.11612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 05/28/2024] [Accepted: 06/07/2024] [Indexed: 07/03/2024] Open
Abstract
Dimensions of body size are an important measurement in animal ecology, although they can be difficult to obtain due to the effort and cost associated with the invasive nature of these measurements. We avoid these limitations by using camera trap images to derive dimensions of animal size. To obtain measurements of object dimensions using this method, the size of the object in pixels, the focal length of the camera, and the distance to that object must be known. We describe a novel approach of obtaining the distance to the object through the creation of a portable distance marker, which, when photographed, creates a "reference image" to determine the position of the animal within an image. This method allows for the retrospective analysis of existing datasets and eliminates the need for permanent in-field distance markers. We tested the accuracy of this methodology under controlled conditions with objects of known size resembling Felis catus, our study species, validating the legitimacy of our method of size estimation. We then apply our method to measure feral cat body size using images collected in Tasmania, Australia. The precision of our methodology was evaluated by comparing size estimates across individual cats, revealing consistent and reliable results. The average height (front paw to shoulder) of the feral cats sampled was 25.25 cm (CI = 24.4, 26.1) and the average length (base of tail to nose) was 47.48 cm (CI = 46.0, 48.9), suggesting wild feral cats in our study area are no larger than their domestic counterparts. Given the success of its application within our study, we call for further trails with this method across a variety of species.
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Affiliation(s)
| | - Barry W. Brook
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
- ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH)University of TasmaniaHobartTasmaniaAustralia
| | - Jessie C. Buettel
- School of Natural SciencesUniversity of TasmaniaHobartTasmaniaAustralia
- ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH)University of TasmaniaHobartTasmaniaAustralia
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Rendall AR, Sutherland DR, Cooke R, White JG. Does the foraging ecology of feral cats change after the eradication of foxes? Biol Invasions 2022. [DOI: 10.1007/s10530-021-02718-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Augusteyn J, Nolan B. Evaluating methods for controlling feral cats that minimise non‐target impacts at Taunton National Park (Scientific). ECOLOGICAL MANAGEMENT & RESTORATION 2021. [DOI: 10.1111/emr.12536] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Augusteyn J, Rich M, Story G, Nolan B. Canids potentially threaten bilbies at Astrebla Downs National Park. AUSTRALIAN MAMMALOGY 2021. [DOI: 10.1071/am20034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The ecological role of canids in arid Australia is unresolved. Some argue they play a role regulating populations of herbivores and introduced mesopredators such as feral cats (Felis catus) and foxes (Vulpes vulpes). However, evidence also suggests they pose a threat to native species populations. The aims of this study were to determine the extent of canid predation on the bilby population at Astrebla Downs National Park, Queensland, to improve our understanding of the ecological role that canids serve in the park and to determine whether seasonal changes in the canid diet can be used to predict if and when management should intervene. Canid scats (n=723) were collected over seven years and their content examined. The percentage of bilby remains in the canid scats varied from 13 to 85% (mean=43%) and was 20–100% by volume. In total, 23 vertebrate species were identified in canid scats. The percentage of cat remains was 0–44% (mean=11%), peaking in 2013 during a cat plague and coinciding with canids actively hunting cats. Fox remains were not detected in dog scats. These results indicate that canids had a varied diet and at times threatened the bilby population at Astrebla.
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Taggart PL, Caraguel CGB, McAllister MM. Fractional seroprevalence rates in common prey species can cause more than half of feral cats to be exposed to Toxoplasma gondii annually. Vet Parasitol 2020; 288:109306. [PMID: 33221602 DOI: 10.1016/j.vetpar.2020.109306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 11/18/2022]
Abstract
Rodents comprise a major component of cat (Felis catus) diets in many ecosystems, and life cycle diagrams of Toxoplasma gondii typically depict small rodents as quintessential intermediate hosts. Counter-intuitively, small rodents often experience a lower T. gondii seroprevalence than do larger sympatric mammals. This observation has repeatedly caused confusion about the relative importance of small rodents to the ecology of T. gondii. To address this confusion, we modified the Reed-Frost epidemic model to develop a simple binomial equation to model T. gondii transmission from prey to feline predators. This equation takes into account variations in prey seroprevalence and the frequency with which they are consumed by felids. Even when T. gondii seroprevalence in prey is < 1%, computation reveals that the risk of feline exposure to T. gondii can easily exceed 50 % annually. For example, if cats eat an average of 1 mouse per day, a seroprevalence of 0.2 % (1/500) in mice will cause 51.9 % of cats to be exposed to T. gondii annually. Our simple equation demonstrates that both prey seroprevalence and the rate at which prey are consumed are of approximately equal importance to the ecology of T. gondii. When inferring the importance of various prey species to the ecology of T. gondii, researchers must consider the predation and dietary habits of felids from within their study system. Our simple binomial equation could also be used to predict T. gondii exposure rates of humans or other carnivorous animals from various dietary sources or be applied to other predator-prey parasite life cycles.
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Affiliation(s)
- Patrick L Taggart
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, 5371, Australia; Vertebrate Pest Research Unit, NSW Department of Primary Industries, Orange, NSW, 2800 Australia.
| | - Charles G B Caraguel
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, 5371, Australia
| | - Milton M McAllister
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, 5371, Australia
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Rowland J, Hoskin CJ, Burnett S. Distribution and diet of feral cats (Felis catus) in the Wet Tropics of north-eastern Australia, with a focus on the upland rainforest. WILDLIFE RESEARCH 2020. [DOI: 10.1071/wr19201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
ContextFeral cats have been identified as a key threat to Australia’s biodiversity, particularly in arid areas and tropical woodlands. Their presence, abundance and potential impacts in rainforest have received less attention.
AimsTo investigate the distribution and diet of feral cats (Felis catus) in upland rainforest of the Wet Tropics.
MethodsWe collated available occurrence records from the Wet Tropics, and data from upland camera-trapping surveys over an 8-year period, to assess geographic and elevational distribution of feral cats in the bioregion. We also assessed the diet of feral cats from scats collected at upland sites.
Key resultsFeral cats are widespread through the Wet Tropics bioregion, from the lowlands to the peaks of the highest mountains (>1600m), and in all vegetation types. Abundance appears to vary greatly across the region. Cats were readily detected during camera-trap surveys in some upland rainforest areas (particularly in the southern Atherton Tablelands and Bellenden Ker Range), but were never recorded in some areas (Thornton Peak, the upland rainforest of Windsor Tableland and Danbulla National Park) despite numerous repeated camera-trap surveys over the past 8 years at some of these sites. Scat analysis suggested that small mammals comprise ~70% of the diet of feral cats at an upland rainforest site. Multivariate analysis could not detect a difference in mammal community at sites where cats were detected or not.
ConclusionsFeral cats are widespread in the Wet Tropics and appear to be common in some upland areas. However, their presence and abundance are variable across the region, and the drivers of this variability are not resolved. Small mammals appear to be the primary prey in the rainforest, although the impacts of cats on the endemic and threatened fauna of the Wet Tropics is unknown.
ImplicationsGiven their documented impact in some ecosystems, research is required to examine the potential impact of cats on Wet Tropics fauna, particularly the many upland endemic vertebrates. Studies are needed on (1) habitat and prey selection, (2) population dynamics, and (3) landscape source–sink dynamics of feral cats in the Wet Tropics.
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Woolley LA, Murphy BP, Geyle HM, Legge SM, Palmer RA, Dickman CR, Doherty TS, Edwards GP, Riley J, Turpin JM, Woinarski JCZ. Introduced cats eating a continental fauna: invertebrate consumption by feral cats (Felis catus) in Australia. WILDLIFE RESEARCH 2020. [DOI: 10.1071/wr19197] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Abstract ContextRecent global concern over invertebrate declines has drawn attention to the causes and consequences of this loss of biodiversity. Feral cats, Felis catus, pose a major threat to many vertebrate species in Australia, but their effect on invertebrates has not previously been assessed. AimsThe objectives of our study were to (1) assess the frequency of occurrence (FOO) of invertebrates in feral cat diets across Australia and the environmental and geographic factors associated with this variation, (2) estimate the number of invertebrates consumed by feral cats annually and the spatial variation of this consumption, and (3) interpret the conservation implications of these results. MethodsFrom 87 Australian cat-diet studies, we modelled the factors associated with variation in invertebrate FOO in feral cat-diet samples. We used these modelled relationships to predict the number of invertebrates consumed by feral cats in largely natural and highly modified environments. Key resultsIn largely natural environments, the mean invertebrate FOO in feral cat dietary samples was 39% (95% CI: 31–43.5%), with Orthoptera being the most frequently recorded order, at 30.3% (95% CI: 21.2–38.3%). The highest invertebrate FOO occurred in lower-rainfall areas with a lower mean annual temperature, and in areas of greater tree cover. Mean annual invertebrate consumption by feral cats in largely natural environments was estimated to be 769 million individuals (95% CI: 422–1763 million) and in modified environments (with mean FOO of 27.8%) 317 million invertebrates year−1, giving a total estimate of 1086 million invertebrates year−1 consumed by feral cats across the continent. ConclusionsThe number of invertebrates consumed by feral cats in Australia is greater than estimates for vertebrate taxa, although the biomass (and, hence, importance for cat diet) of invertebrates taken would be appreciably less. The impact of predation by cats on invertebrates is difficult to assess because of the lack of invertebrate population and distribution estimates, but cats may pose a threat to some large-bodied narrowly restricted invertebrate species. ImplicationsFurther empirical studies of local and continental invertebrate diversity, distribution and population trends are required to adequately contextualise the conservation threat posed by feral cats to invertebrates across Australia.
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The short-term response of feral cats to rabbit population decline: Are alternative native prey more at risk? Biol Invasions 2019. [DOI: 10.1007/s10530-019-02131-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Woolley L, Geyle HM, Murphy BP, Legge SM, Palmer R, Dickman CR, Augusteyn J, Comer S, Doherty TS, Eager C, Edwards G, Harley DK, Leiper I, McDonald PJ, McGregor HW, Moseby KE, Myers C, Read JL, Riley J, Stokeld D, Turpin JM, Woinarski JC. Introduced catsFelis catuseating a continental fauna: inventory and traits of Australian mammal species killed. Mamm Rev 2019. [DOI: 10.1111/mam.12167] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Leigh‐Ann Woolley
- NESP Threatened Species Recovery Hub Research Institute for the Environment and Livelihoods Charles Darwin University Casuarina NT0909Australia
| | - Hayley M. Geyle
- NESP Threatened Species Recovery Hub Research Institute for the Environment and Livelihoods Charles Darwin University Casuarina NT0909Australia
| | - Brett P. Murphy
- NESP Threatened Species Recovery Hub Research Institute for the Environment and Livelihoods Charles Darwin University Casuarina NT0909Australia
| | - Sarah M. Legge
- NESP Threatened Species Recovery Hub Centre for Biodiversity and Conservation Science University of Queensland St Lucia Qld4072Australia
- Fenner School of Environment and Society The Australian National University Canberra ACT2602Australia
| | - Russell Palmer
- Department of Biodiversity, Conservation and Attractions Locked Bag 104, Bentley Delivery Centre WA 6983 Australia
| | - Christopher R. Dickman
- NESP Threatened Species Recovery Hub, Desert Ecology Research Group School of Life and Environmental Sciences A08 University of Sydney NSW2006Australia
| | - John Augusteyn
- Queensland Parks and Wildlife Service PO Box 3130Red HillQld4701Australia
| | - Sarah Comer
- Department of Biodiversity, Conservation and Attractions South Coast Region Albany WA6330Australia
| | - Tim S. Doherty
- Centre for Integrative Ecology School of Life and Environmental Sciences (Burwood Campus) Deakin University Geelong Vic3220Australia
| | | | - Glenn Edwards
- Department of Environment and Natural ResourcesAlice Springs NT0871Australia
| | - Dan K.P. Harley
- Wildlife Conservation and Science Department Zoos Victoria PO Box 248 Healesville Vic.3777Australia
| | - Ian Leiper
- NESP Threatened Species Recovery Hub Research Institute for the Environment and Livelihoods Charles Darwin University Casuarina NT0909Australia
| | - Peter J. McDonald
- Department of Environment and Natural ResourcesAlice Springs NT0871Australia
| | - Hugh W. McGregor
- NESP Threatened Species Recovery Hub School of Biological Sciences University of Tasmania Private Bag 55 Hobart Tas7001Australia
| | | | - Cecilia Myers
- Dunkeld Pastoral Co Pty Ltd P.O. Box 50 Dunkeld Vic3294Australia
| | - John L. Read
- School of Earth and Environmental Sciences University of Adelaide Adelaide SA5000Australia
| | - Joanna Riley
- School of Biological Sciences University of Bristol 24 Tyndall Ave BristolBS8 1TQUK
| | - Danielle Stokeld
- Department of Environment and Natural ResourcesBerrimah NT0828Australia
| | - Jeff M. Turpin
- Department of Terrestrial Zoology Western Australian Museum 49 Kew Street Welshpool WA6106Australia
| | - John C.Z. Woinarski
- NESP Threatened Species Recovery Hub Research Institute for the Environment and Livelihoods Charles Darwin University Casuarina NT0909Australia
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Tatler J, Prowse TAA, Roshier DA, Allen BL, Cassey P. Resource pulses affect prey selection and reduce dietary diversity of dingoes in arid Australia. Mamm Rev 2019. [DOI: 10.1111/mam.12157] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jack Tatler
- School of Biological SciencesUniversity of Adelaide Adelaide SA 5005 Australia
| | - Thomas A. A. Prowse
- School of Mathematical SciencesUniversity of Adelaide Adelaide SA 5005 Australia
| | - David A. Roshier
- Australian Wildlife Conservancy PO Box 8070 Subiaco East WA 6008 Australia
- Australia Centre for Ecosystem ScienceUniversity of New South Wales Sydney NSW 2052 Australia
| | - Benjamin L. Allen
- Institute for Life Sciences and the EnvironmentUniversity of Southern Queensland Toowoomba Queensland 4350 Australia
| | - Phillip Cassey
- School of Biological SciencesUniversity of Adelaide Adelaide SA 5005 Australia
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Nano CEM, Randall DJ, Stewart AJ, Pavey CR, McDonald PJ. Spatio-temporal gradients in food supply help explain the short-term colonisation dynamics of the critically endangered central rock-rat ( Zyzomys pedunculatus
). AUSTRAL ECOL 2019. [DOI: 10.1111/aec.12753] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Catherine E. M. Nano
- Flora and Fauna Division; Department of Environment and Natural Resources; Northern Territory Government; Alice Springs Northern Territory 0870 Australia
| | - Debbie J. Randall
- Flora and Fauna Division; Department of Environment and Natural Resources; Northern Territory Government; Alice Springs Northern Territory 0870 Australia
| | - Alistair J. Stewart
- Flora and Fauna Division; Department of Environment and Natural Resources; Northern Territory Government; Alice Springs Northern Territory 0870 Australia
| | - Chris R. Pavey
- Land & Water; CSIRO; Winnellie Northern Territory Australia
| | - Peter J. McDonald
- Flora and Fauna Division; Department of Environment and Natural Resources; Northern Territory Government; Alice Springs Northern Territory 0870 Australia
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Parsons MH, Banks PB, Deutsch MA, Munshi-South J. Temporal and Space-Use Changes by Rats in Response to Predation by Feral Cats in an Urban Ecosystem. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00146] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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Woinarski JCZ, Murphy BP, Palmer R, Legge SM, Dickman CR, Doherty TS, Edwards G, Nankivell A, Read JL, Stokeld D. How many reptiles are killed by cats in Australia? WILDLIFE RESEARCH 2018. [DOI: 10.1071/wr17160] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context Feral cats (Felis catus) are a threat to biodiversity globally, but their impacts upon continental reptile faunas have been poorly resolved. Aims To estimate the number of reptiles killed annually in Australia by cats and to list Australian reptile species known to be killed by cats. Methods We used (1) data from >80 Australian studies of cat diet (collectively >10 000 samples), and (2) estimates of the feral cat population size, to model and map the number of reptiles killed by feral cats. Key results Feral cats in Australia’s natural environments kill 466 million reptiles yr–1 (95% CI; 271–1006 million). The tally varies substantially among years, depending on changes in the cat population driven by rainfall in inland Australia. The number of reptiles killed by cats is highest in arid regions. On average, feral cats kill 61 reptiles km–2 year–1, and an individual feral cat kills 225 reptiles year–1. The take of reptiles per cat is higher than reported for other continents. Reptiles occur at a higher incidence in cat diet than in the diet of Australia’s other main introduced predator, the European red fox (Vulpes vulpes). Based on a smaller sample size, we estimate 130 million reptiles year–1 are killed by feral cats in highly modified landscapes, and 53 million reptiles year–1 by pet cats, summing to 649 million reptiles year–1 killed by all cats. Predation by cats is reported for 258 Australian reptile species (about one-quarter of described species), including 11 threatened species. Conclusions Cat predation exerts a considerable ongoing toll on Australian reptiles. However, it remains challenging to interpret the impact of this predation in terms of population viability or conservation concern for Australian reptiles, because population size is unknown for most Australian reptile species, mortality rates due to cats will vary across reptile species and because there is likely to be marked variation among reptile species in their capability to sustain any particular predation rate. Implications This study provides a well grounded estimate of the numbers of reptiles killed by cats, but intensive studies of individual reptile species are required to contextualise the conservation consequences of such predation.
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Spencer EE, Newsome TM, Dickman CR. Prey selection and dietary flexibility of three species of mammalian predator during an irruption of non-cyclic prey. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170317. [PMID: 28989739 PMCID: PMC5627079 DOI: 10.1098/rsos.170317] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 08/16/2017] [Indexed: 05/28/2023]
Abstract
Predators often display dietary shifts in response to fluctuating prey in cyclic systems, but little is known about predator diets in systems that experience non-cyclic prey irruptions. We tracked dietary shifts by feral cats (Felis catus), red foxes (Vulpes vulpes) and dingoes (Canis dingo) through a non-cyclic irruption of small mammalian prey in the Simpson Desert, central Australia. We predicted that all three predators would alter their diets to varying degrees as small mammals declined post irruption, and to test our predictions we live-trapped small mammals through the irruption event and collected scats to track predator diets. Red foxes and dingoes included a broader variety of prey in their diets as small mammals declined. Feral cats did not exhibit a similar dietary shift, but did show variable use and selectivity of small mammal species through the irruption cycle. Results were largely consistent with prior studies that highlighted the opportunistic feeding habits of the red fox and dingo. They also, however, showed that feral cats may exhibit less dietary flexibility in response to small mammal irruptions, emphasizing the importance of tracking predator diets before, during and after irruption events.
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Affiliation(s)
- Emma E. Spencer
- Desert Ecology Research Group, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Thomas M. Newsome
- Desert Ecology Research Group, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
- School of Life and Environmental Sciences, Deakin University (Burwood Campus), Geelong, Victoria 3125, Australia
- Global Trophic Cascades Program, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA
| | - Christopher R. Dickman
- Desert Ecology Research Group, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia
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Dickman CR, Newsome TM. Individual hunting behaviour and prey specialisation in the house cat Felis catus: Implications for conservation and management. Appl Anim Behav Sci 2015. [DOI: 10.1016/j.applanim.2014.09.021] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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