The ecology and behaviour of feral ferrets (Mustela furo) in Canterbury farmland, New Zealand.
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Ferret (Mustela furo) control programs, especially those attempting to prevent the spread of Mycobacterium bovis (Tb), would greatly benefit from practical knowledge of ferret ecology and behaviour. This study had two main objectives: firstly, to investigate ferret ecology by examining ferret abundance, survival, trapping success, and diet; and, secondly, to investigate ferret behaviour and activity patterns by using an acoustically sensitive transmitter system (ASTS). Abundance and survival estimates of ferrets tagged with passive integrated transponders (PITs), showed a marked seasonal variation, and despite ferrets being controlled on one site, data from both sites showed that lagomorph numbers increased exponentially. A trapping success model (GLIM) showed that factors such as vegetation cover, rabbit sign, and animal tracks positively influenced capture rates. Although GPS technology provided accurate trap location data, trapping success also benefited from understanding the distribution signs of both predators and prey. GPS data further contributed to GIS models of animal movements, home range and site fidelity. As a result, trapping success was found to be affected by periods of low ferret abundance, fluctuations in trappability and possibly excess prey. It was found that, even though cats and ferrets use different hunting strategies, lagomorphs were their staple prey in North Canterbury. Unlike overseas habitats, New Zealand farmland lacks alternative suitable prey and this may explain the narrow diet of both predators. Even with the large increase in lagomorph numbers seen in North Canterbury in the second year of study, the diets of both predators remained the same, suggesting that these predators are unable to regulate lagomorphs once their numbers cross a certain threshold. By using ASTS technology to examine ferret behaviour and activity it was possible to identify a wider range of behaviours than previously documented using conventional radio tracking techniques. Despite using only one ferret, it was not only possible to document the time of an activity period, the length of each behaviour, as well as seasonal changes in activity, but also behaviours rarely recorded by researchers using more conventional techniques. Generally the ferret displayed an ultradian activity pattern, disputing the accepted nocturnal hypothesis. One implication for ferret control programs using baited traps was a documented decrease in eating behaviour during the breeding seasons. Nevertheless, this study provided as many questions as it did answers; however, with technology such as ASTS, further information about the behaviour and ecology of ferrets could advance future ferret control programs.