Detecting the elusive Scottish wildcat Felis silvestris silvestris using camera trapping K ERRY K ILSHAW,PAUL J. JOHNSON A NDREW C. KITCHENER and D AVID W. MACDONALD Abstract Population monitoring is important for (e.g. Gese, 2001). Monitoring carnivores is challenging conservation management but difficult to achieve for rare, because they are often threatened and exist at low densities cryptic species. Reliable information about the Critically and in fragmented populations (Gese, 2001). Carnivores Endangered Scottish wildcat Felis silvestris silvestris is suffer from many, mostly anthropogenic, threats, including lacking because of difficulties in morphological and genetic direct persecution, habitat loss and competition with identification, resulting from extensive hybridization with humans for prey. Lack of information on the current status feral domestic cats Felis catus. We carried out camera-trap of many carnivores may be hindering effective conservation surveys in the Cairngorms National Park, UK, to examine action (Gittleman et al., 2001). the feasibility of camera trapping, combined with a pelage The Scottish wildcat is a subpopulation of the European identification method, to monitor Scottish wildcats. Camera wildcat Felis silvestris silvestris and is Britain’s only surviv- trapping detected individually identifiable wildcats. Of 13 ing native felid (Macdonald et al., 2004). Although widely individual wild-living cats, four scored as wildcats based distributed (Africa, Asia, Europe) and categorized as Least on pelage characters and the rest were wildcat × domestic Concern (Driscoll & Nowell, 2009), this species is subject cat hybrids. Spatially explicit capture–recapture density to several threats globally, resulting in local extinctions and estimation methods generated a density of wild-living cats population fragmentation, especially in Europe (Nowell & 2 (wildcats and hybrids) of 68.17 ± SE 9.47 per 100 km . The Jackson, 1996). Recent estimates, from the proportion of cats impact of reducing trapping-grid size, camera-trap numbers with wildcat pelage from a 1990s sample, indicate the and survey length on density estimates was investigated Scottish population may be Critically Endangered, with using spatially explicit capture–recapture models. Our find- , 400 genetically pure individuals remaining (Kitchener ings indicate camera trapping is more effective for monitor- et al., 2005; Driscoll & Nowell, 2009). Once widespread ing wildcats than other methods currently used and capture across Britain, habitat loss (Nowell & Jackson, 1996), per- success could be increased by using bait, placing camera secution (Langley & Yalden, 1977; Tapper, 1992; Kitchener, stations < 1.5 km apart, increasing the number of camera 1995) and hybridization with feral domestic cats Felis catus stations, and surveying for 60–70 days. This study shows (McOrist et al., 1991; Hubbard et al., 1992; Beaumont et al., that camera trapping is effective for confirming the presence 2001; Daniels et al., 2001) have now restricted wildcats to of the wildcat in potential target areas for conservation northern Scotland (Balharry & Daniels, 1998; Daniels et al., management. 1998; Davies & Gray, 2010). Hybridization is currently considered the greatest threat Keywords Camera trapping, Felis silvestris silvestris, to this species (Nowell & Jackson, 1996; Macdonald et al., monitoring, Scotland, Scottish wildcat, spatially explicit 2004, 2010). Documented since the 18th century (Berwick, capture–recapture 1920), hybridization has potentially occurred since domestic cats arrived in Britain 2,000–3,000 years ago (Clutton- Brock, 1987; Serpell, 2000). Extensive introgressive hybridi- Introduction zation has led to difficulties in distinguishing Scottish wildcats from some wildcat × feral cat hybrids, complic- onitoring wildlife populations is important for ating enforcement of protective legislation, hindering conservation management but is often difficult to M monitoring and making management potentially ineffective achieve effectively, particularly for rare and cryptic species (Macdonald et al., 2004, 2010). Kitchener et al. (2005) iden- tified seven principal and eight subsidiary pelage characters KERRY KILSHAW (Corresponding author) PAUL J. JOHNSON and DAVID to distinguish Scottish wildcats from hybrids and feral W. MACDONALD Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanti–Kaplan Centre, Tubney House, domestic cats, providing an objective method for identifying Abingdon Road, Tubney, Oxfordshire, OX13 5QL, UK wild-living cats in the field. Monitoring methods for E-mail [email protected] wildcats to date include road traffic accident surveys, live ANDREW C. KITCHENER Department of Natural Sciences, National Museums trapping, interviews and questionnaires, or combinations Scotland, Edinburgh, and Institute of Geography, School of GeoSciences, 1991 1998 University of Edinburgh, Edinburgh, UK of these (Easterbee et al., ; Balharry & Daniels, ; 1998 2010 Received 21 August 2012. Revision requested 11 January 2013. Daniels et al., ; Davies & Gray, ). Although these Accepted 5 August 2013. First published online 7 May 2014. methods generate useful data, each has limitations. For Oryx, 2015, 49(2), 207–215 © 2014 Fauna & Flora International doi:10.1017/S0030605313001154 Downloaded from https://www.cambridge.org/core. IP address: 170.106.40.139, on 01 Oct 2021 at 14:32:32, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605313001154 208 K. Kilshaw et al. FIG. 1 The study site at the Seafield and Strathspey Estates, showing the locations of the camera-trap stations and their associated habitat: suitable (woodland, scrub and pasture/grassland) and unsuitable (arable, urban/suburban, heather moorland, bog and montane). The rectangle on the inset indicates the location of the main figure in north-east Scotland. A, B, C and D refer to the subsets of camera traps used in the spatially explicit capture–recapture analysis examining how a reduction in survey area affects density estimates. example, road traffic accident surveys may be biased towards Special Scientific Interest. Comprising a mixture of heather hybrids and feral cats, which scavenge more frequently moorland, Scots pine Pinus sylvestris plantations, birch on roads as a result of competition with larger wildcats woodland (Betula sp.) and rough grazing, the site supports (A. Kitchener, unpubl. data). Live trapping is time con- diverse wildlife, including Scottish wildcats. Traditionally suming, and requires experience and licensing under British used for red grouse Lagopus lagopus scotica shooting and law. Information from questionnaires and interviews deer stalking, predator control was important for estate depends on respondent experience and this method is management. Although the estate is now primarily used liable to observer error (Davies & Gray, 2010). Also, except for tourism and deer stalking, predator control continues, for the survey of Davies & Gray (2010), most data on mainly to protect capercaillie Tetrao urogallus leks (Seafield Scottish wildcats were collected before the development & Strathspey Estates, 2001). The estate was selected because of the current pelage identification method. Given the putative wildcats had been seen by gamekeepers and wild- limitations and biases of existing methods, exploring living cats were present regularly (Estate manager, pers. other survey methodologies, such as camera trapping, is comm., 2009). desirable. Camera trapping can provide much useful data (e.g. Methods Karanth & Nichols, 1998, 2002; Carbone et al., 2001), including population-density estimates for monitoring Twenty camera trap stations were placed in a 4 × 5 grid. 2001 2007 studies (Yoccoz et al., ; Martin et al., ). Presence Based on the minimum home range of female Scottish and abundance of European wildcats have been determined wildcats (Corbett, 1979; Daniels et al., 2001), stations were from camera trapping, which has also allowed individual located 0.8–1.5 km apart so that individuals with the smallest fi 2005 2009 identi cation (Monterroso et al., ; Anile et al., ; recorded home range had a probability of . 0 of encounter- 2009 1 Sarmento et al., ). This study aimed to ( ) determine the ing a station (Karanth & Nichols, 1998). Two Cuddleback feasibility of camera trapping for surveying and monitoring Capture 3.0 (Cuddleback Digital, Green Bay, USA) camera 2 Scottish wildcats, ( ) compare the success of baited, scented traps were used per station. The first station was located 3 and unbaited camera traps, and ( ) develop a camera where a cat with wildcat-type pelage had recently been trapping protocol for future surveys. Population-density trapped alive and released following standard estate pre- ff estimates under di erent models were generated using dator control practices. The remaining 19 stations were – spatially explicit capture recapture analysis. arranged around this site. Stations were located where either wild-living cat signs (footprints, scats, dens, scrape marks) Study area were present or where there were signs of pine martens Martes martes (which have similar habitat and prey require- The study was carried out on Seafield and Strathspey Estates ments to the Scottish wildcat; Balharry, 1993; Birks et al., in north-east Scotland (Fig. 1), partly within the Cairngorms 2005) or rabbits Oryctolagus cuniculus (e.g. burrows, sight- 2 National Park, of which 57.6 km is designated a Site of ings, footprints,