Mammalia 2018; 82(6): 550–564 Elizabeth Croose*, J.W. Duckworth, Sandrine Ruette, Dmitry V. Skumatov, Vyacheslav V. Kolesnikov and Alexander P. Saveljev A review of the status of the Western polecat Mustela putorius: a neglected and declining species? https://doi.org/10.1515/mammalia-2017-0092 Received July 14, 2017; accepted January 18, 2018; previously Introduction published online February 19, 2018 Monitoring the distribution and abundance of species is Abstract: The Western polecat Mustela putorius has a fundamental to the conservation, research and manage- widespread European distribution and is currently listed ment of wildlife populations (Wilson and Delahay 2001). as Least Concern by the IUCN Red List of Threatened Spe- The International Union for Conservation of Nature and cies. Reports are increasing of polecat population declines Natural Resources (IUCN) Red List of Threatened Species in several countries, although a paucity of data means assessments provide information that is essential to guide population trends are poorly understood. This paper species conservation efforts and management of natural reviews and summarises information on the polecat’s sta- resources at multiple scales, inform national development tus and range-wide population trends. Information and policies and legislation, and produce recommendations opinion were gathered for 34 countries, from individuals for conservation action (Rodrigues et al. 2006). and organisations studying polecats and from reviewing The Western or European polecat Mustela putorius the literature and national Red Lists. Where trends were (hereafter referred to as the polecat) is a medium-sized car- identified, the polecat population is known or suspected nivore of the family Mustelidae and is the ancestor of the to be declining in 20 countries, reported to be stable in domestic ferret Mustela furo (Sato et al. 2003, Costa et al. five countries, stable or increasing in one country, and 2013). It is widespread in the western Palaearctic, ranging increasing in two countries. For many countries, data are from the Atlantic coast of Iberia in the west to the Ural so limited in quantity or spatial scale, or at risk of bias, Mountains in the Russian Federation in the east, but is that trends could not be identified or confidence in trend naturally absent from Ireland, northern Scandinavia, part assessments is low. The main drivers of polecat decline of the Balkans and the eastern Adriatic coast (Mitchell- are poorly understood, but might include habitat deg- Jones et al. 1999). Additionally, populations of wild- living radation; changes in prey availability; competition with polecat- or ferret-like animals of unresolved taxonomic invasive carnivores; poisoning; conflict with human inter- identity, but which are believed to be native, occur in ests; harvesting and killing of polecats; and hybridisation. Morocco and Algeria (Gippoliti 2011, Ahmim 2013). Robust survey methods and systematic monitoring pro- The polecat’s preferred habitat type varies across its grammes are urgently needed to gather up-to-date data on range but includes riparian vegetation and water courses polecat population trends across the species’ range. (Zabala et al. 2005, Rondinini et al. 2006, Mestre et al. 2007), grasslands, pastures, human settlements (Baghli Keywords: Mustela putorius; population status; popula- et al. 2005), woodland edge, agricultural land (Birks and tion trend; status review; Western polecat. Kitchener 1999) and montane pine forests (Virgós 2003). The polecat’s diet has been described as generalist, com- prising mainly rodents, amphibians, lagomorphs, birds *Corresponding author: Elizabeth Croose, The Vincent Wildlife and carrion (Lodé 1997). However, this varies across the Trust, 3&4 Bronsil Courtyard, Eastnor, Ledbury, Herefordshire HR8 polecat’s range and is more specialised in some areas; for 1EP, UK, e-mail: [email protected] example, it is dominated by European rabbit Oryctolagus J.W. Duckworth: 6 Stratton Road, Saltford, Bristol BS31 3BS, UK cuniculus in Mediterranean regions (Santos et al. 2009) Sandrine Ruette: Office National de la Chasse et de la Faune and Britain (Birks and Kitchener 1999); by amphibians, Sauvage, Montfort, F 1330 Birieux, France Dmitry V. Skumatov, Vyacheslav V. Kolesnikov and Alexander P. specifically anurans, in Switzerland (Weber 1989), France Saveljev: Russian Research Institute of Game Management and Fur (Lodé 1997) and Denmark (Hammershøj et al. 2004); and Farming, 79 Preobrazhenskaya Str., Kirov 610000, Russia by small rodents, notably the common vole Microtus arvalis Brought to you by | Michigan State University Authenticated Download Date | 11/8/18 4:47 PM E. Croose et al.: A review of the status of the Western polecat 551 and field mouse Apodemus sp., in western Poland (Malecha considerable concern. During the Red List assessment, and Antczak 2013) and Hungary (Lanszki and Heltai 2007). the polecat was deemed the most difficult of all small The polecat is listed on Appendix III of the Con- carnivore species to categorise, the confidence in the cat- vention on the Conservation of European Wildlife and egorisation is low and the widespread uncertainty of the Natural Habitats (Bern Convention) (Council of Europe polecat’s status in many countries indicated that further 2016) and Annex V of the EU Council’s Directive on the action was warranted. conservation of natural habitats and of wild fauna and This paper reviews and presents up-to-date informa- flora (EU Habitats Directive) (European Environment tion on the current status and population trends for the Agency undated). In many countries, the polecat is polecat across its range and discusses the potential drivers legally hunted for fur (for example, Russia and Scandina- and implications of these trends. via), or trapped as a perceived pest species (for example, Croatia and France), and it receives some level of legal protection in other countries (for example, Britain and Luxembourg) (Skumatov et al. 2016). Materials and methods The polecat occurs at a low population density, is Information on the polecat’s status and population trends typically nocturnal and leaves few distinctive field signs, was gathered by two means. Firstly, a literature search which makes the species difficult to monitor system- was undertaken using Google search, Google Scholar and atically (Birks 1997). The main methods used to study online library databases to source published and grey lit- and monitor polecats are live trapping (e.g. Birks 1997, erature. The keywords used in the search were polecat, Baghli et al. 2005), radio-telemetry (Birks and Kitchener Western polecat, European polecat and Mustela puto- 1999, Baghli et al. 2005, Rondinini et al. 2006), analysis rius. Relevant literature was scanned for any information of game bag and pelt harvesting data, and collection of on the polecat’s status and population trends. Secondly, road casualties and other, mostly incidental, records such organisations, researchers and biologists who may hold as live sightings (Birks and Kitchener 1999, Birks 2008, information on polecats, in countries where the species is Barrientos and Bolonio 2009, Barrientos and Miranda known to occur, were identified and contacted. Individu- 2012, Croose 2016). als and organisations were contacted if they were known A paucity of data means that population trends for the to be studying polecats, had authored papers or reports on polecat across its range are poorly understood. However, polecats, had contributed to the IUCN Red List assessment in recent years there have been reports of population or Red List assessments in their own countries, or engaged declines in several countries (Skumatov et al. 2016). In in activities that generated many polecat records. Corre- light of this, in 2014–2016 the category for the polecat, spondents were contacted via email or ResearchGate. Least Concern, was reviewed. As part of this assess- Correspondents were asked to classify the polecat popula- ment, researchers from several countries in the polecat’s tion in their country into one of the following categories: range reported, notwithstanding the known increases increasing, stable, declining, unknown/data deficient. in some countries (representing recoveries from severe They were also asked to highlight any relevant literature historical declines), that the polecat population was in which population trends are listed and identify other declining, or suspected to be declining, and others had individuals or organisations that might hold information insufficient data to inform population trends. Neverthe- on polecats. Finally, national Red Lists were reviewed to less, the overall global population trend for the polecat ascertain the category to which the polecat was assigned. was deemed unlikely to reach the rate of decline that In several countries within the polecat’s range, neither would make a Near Threatened categorisation appropri- published information on polecats nor individuals or ate (an overall loss of 20%, or more, of the global popu- organisations working on polecats were traced and nor lation over the preceding 13 years (three generations), had the species been assessed in the country’s national an anticipated such loss over the next 13 years, or such a Red List. Information was gathered from 2014 to 2017. rate of loss over a 13-year period part before and part after 2016). Thus, the global categorisation remained as Least Concern ( Skumatov et al. 2016). The structure of the Red List