PEST RISK ASSESSMENT Ferret/Polecat Mustela furo and M. putorius (Photo: Malene Thyssen. Image from Wikimedia Commons under a GNU Free Documentation License, Version 1.2) February 2011 Department of Primary Industries, Parks, Water and Environment Resource Management and Conservation Division Department of Primary Industries, Parks, Water and Environment 2011 Information in this publication may be reproduced provided that any extracts are acknowledged. This publication should be cited as: DPIPWE (2011) Pest Risk Assessment: Ferret/Polecat (Mustela furo and M. putorius). Department of Primary Industries, Parks, Water and Environment. Hobart, Tasmania. About this Pest Risk Assessment This pest risk assessment is developed in accordance with the Policy and Procedures for the Import, Movement and Keeping of Vertebrate Wildlife in Tasmania (DPIPWE 2011). The policy and procedures set out conditions and restrictions for the importation of controlled animals pursuant to s32 of the Nature Conservation Act 2002. This pest risk assessment is prepared by DPIPWE for the use within the Department. For more information about this Pest Risk Assessment, please contact: Wildlife Management Branch Department of Primary Industries, Parks, Water and Environment Address: GPO Box 44, Hobart, TAS. 7001, Australia. Phone: 1300 386 550 Email: [email protected] Visit: www.dpipwe.tas.gov.au Disclaimer The information provided in this Pest Risk Assessment is provided in good faith. The Crown, its officers, employees and agents do not accept liability however arising, including liability for negligence, for any loss resulting from the use of or reliance upon the information in this Pest Risk Assessment and/or reliance on its availability at any time. Animal Risk Assessment: Ferret (Mustela furo and M. putorius) 2/22 1. Summary The origin of domesticated ferrets (Mustela furo) is uncertain. They are considered to have been domesticated from wild European polecats (M. putorius) around 1000BC, and were used by the Romans to catch rabbits. The native distribution of the European polecat is in Western Europe. Ferrets have established wild populations in New Zealand, the United Kingdom, Sardinia and Sicily. The ferret was introduced into New Zealand in 1867. During the 1880s and 1890s ferrets were bred and intentionally released to control rabbits. Thousands of ferrets were released, and the species is now established on the North and South Islands. Ferrets have had a devastating effect on native birds and other wildlife in New Zealand. The rapid decline in kiwi populations has been attributed to predation by ferrets and other introduced vertebrates. Ferrets are also thought to contribute to the spread of bovine tuberculosis in New Zealand, and farmers conduct extensive campaigns to kill ferrets in order to remove the vector for this disease. Ferrets are a potential vector for human diseases and can cause painful bites. The species is currently a controlled animal in Tasmania under the Nature Conservation Act 2002, and it is an offence to cause or allow ferrets to go at large in the State. Climate matching suggests that there is an extreme risk that ferrets could establish populations in Tasmania. In New Zealand ferrets feed on mammals, birds, invertebrates and reptiles. Ferrets could impact many native reptiles, insects, birds and mammals in Tasmania, including threatened species such as the New Holland Mouse, Eastern Barred Bandicoot, Tasmanian Devil, and the Forty Spotted Pardalote. This risk assessment concludes that the likelihood that ferrets will establish wild populations in Tasmania is extreme and the potential consequences are also extreme. Ferrets have been categorised as an Extreme Threat to Tasmania. Based on this assessment it is recommended that ferrets are placed on the list of species that are not permitted to be imported into the State. Recommendations for managing domestic ferrets are also provided. Implementation of these recommendations will require stakeholder consultation. Animal Risk Assessment: Ferret (Mustela furo and M. putorius) 3/22 2. Introduction 2.1 NAME AND TAXONOMY Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Mustelidae Genus: Mustela Photo: Malene Thyssen. Image from Wikimedia Commons Photo: Maleneunder Thyssen. a GNU Image Free Documentation from Wikimedia License, Commons Version 1.2 Species: M. putorius and M. furo Sub-species or variety: Mustela putorius furo Common names: Ferret, domestic ferret, polecat, European polecat, forest polecat, fitch, New Zealand fitch, foul-marten Close relatives: Several other similar mammals in the family Mustelidae also share the common name ‘ferret’, however all ferrets currently in Australia come from the domesticated form of M. putorius. The domesticated form is commonly classed as the subspecies Mustela putorius furo, and sometimes as a separate species (M. furo) (Davison et al. 1999). However, as they are genetically indistinguishable and readily able to interbreed with wild M. putorius (Davison et al. 1999; King 1990), this risk assessment subsequently refers to ferrets as M. putorius, but covers all those that may be classed as belonging to the species and subspecies listed above. 2.2 DESCRIPTION The ferret (Mustela putorius) is a small carnivorous mammal with a long, narrow body 20-46cm in length and short legs. Ferrets have short, forward facing ears and a fully-furred tail of 7-14cm. They have large canines and five non-retractable claws on each foot. Juveniles appear similar to adults. Adult ferrets are sexually dimorphic with wild females weighing 205-915g and the heavier males 405-1710g, but otherwise sexes are alike (Blandford 1987). Typically ferrets are dark brown to black in colour, with pale yellow underfur and dark-tipped guard hairs. Most ferrets have a grey/white face that has a distinct masked appearance and numerous tactile facial bristles. Less frequent colours include chocolate, white and red, with albinos not uncommon. Ferrets, particularly males, have a strong musky smell, released from anal scent glands, which is possibly used to mark territory (Blandford 1987). Ferrets walk with their body low, sniffing the ground for scent trails, and they run with their back arched. Ferrets have poor eyesight, relying on smell and hearing as their main senses. They occasionally stand on their hind limbs to get a better view of their surroundings. Ferrets will occasionally swim, and can do so well, but are fairly poor climbers (Long, 2003). Animal Risk Assessment: Ferret (Mustela furo and M. putorius) 4/22 2.3 CONSERVATION AND LEGAL STATUS CONSERVATION STATUS In its natural range, M. putorius is listed as of Least Concern under the International Union for Conservation of Nature (IUCN) Red List due to its wide distribution, large population, and the fact it is unlikely to be declining at a rate required to qualify for listing in a threatened category (Fernandes et al. 2008). Ferrets belong to the genus Mustela, of which there are 14 species (15 if domestic ferrets are classified as M. furo). Of these 14, four species (including M. furo) are listed on the Global Invasive Species Database (GISD) and one (the stoat, M. erminea) is listed as one of the world’s worst 100 invasive species. LEGAL STATUS AUSTRALIA M. putorius is not listed under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (the EPBCA). A draft risk assessment was prepared for the Commonwealth in 2005 concerning the import of ferrets into Australia (Olsen and Jensz 2005) and ferrets were subsequently rejected for inclusion on the list of species suitable for import into Australia. On the basis of their pest potential ferrets are listed under the Extreme Threat category of the current List of Exotic Vertebrate Animals in Australia (VPC 2006), which recommends any animal listed as an Extreme Threat not be allowed to enter or be kept in any state or territory. Ferrets are listed as a Class 1 Pest Animal in Queensland under the Land Protection (Pest and Stock Route Management) Act 2002 and are subject to eradication from the state. It is prohibited to import, keep, introduce or supply a Class 1 pest in Queensland under the Act. Ferrets are listed as a Restricted Animal in the Northern Territory under the Territory Parks and Wildlife Conservation Act. It is illegal to import or keep ferrets in the Territory under the Act. Ferrets can only be kept under licence in Victoria and the ACT, however they may be kept as pets in Tasmania, Western Australia, New South Wales and South Australia. There are currently no restrictions on keeping, breeding or selling ferrets within Tasmania, however deliberately releasing ferrets into the wild is prohibited under the Tasmanian Nature Conservation Act 2002. Animal Risk Assessment: Ferret (Mustela furo and M. putorius) 5/22 3. Biology and Ecology 3.1 LIFE HISTORY Most studies on reproduction in ferrets have been on captive domesticated animals. Female ferrets quickly reach sexual maturity at 8-12 months, while males don’t seem to produce viable sperm until 2 years of age (Kristiansen et al. 2007). The reproductive season in captive animals is usually from March to September and this is consistent with the limited data from wild populations (Lindberg 2008), however there is a peak in mating activity in wild populations around August (Kristiansen et al. 2007). Females are considered seasonally polyoestrus, however individuals may exhibit a constant oestrus for the entire season if not mated (Lindberg 2008). Gestation typically lasts 41 days and captive animals give birth to between one and 18 young with an average of eight (Lindberg 2008). One study suggested that wild European ferrets in Denmark produced an average of 6 young per litter, with yearling females conceiving at the same rate and producing the same size litters as more mature individuals (Kristiansen et al. 2007). Young are born around October or November in a den located under cover such as a hollow log or in the burrow of another animal. Ferrets are highly adaptable in their choice of a den site, with individuals known to have used farm buildings.