Practical considerations for the field study of American mink Mustela vison in lowland England.

Abstract

Because feral American mink are a successful alien carnivore worldwide, demands for field studies are likely to grow. Appropriate methods for trapping, use of anaesthesia, handling and radio-tracking are important from both academic and animal welfare view points. From accumulated field studies of mink over the last 30 years, including our own, we describe the problems that researchers will likely face in the field, and offer possible solutions for them. Surveys in the breeding and kit dispersal seasons likely inflate the estimated populations, and the best time to assess a local mink population is kit rearing season (May to July in the UK). The best trapping sites occur in the junction between a hedge/ditch and waterside cover. A mass of dry hay, with which the traps are wrapped, prevents mink from damaging their teeth. In the field mink is safely anaesthetised using a combination of a volatile agent (isoflurane), and injectable agents (medetomidine and ketamine mixture), which produces anaesthesia lasting for 60 minutes or more, and is reversible with another injectable agent (atipamezole). In lowland England triangulation is not necessary to locate animals by radio-tracking although obtaining radio signals is problematic when animals are under ground.