Ferret (mustela furo) abundance, survival and recruitmenton farmland in north canterbury, new zealand

Abstract

Few estimates of ferret (Mustela furo) abundance and survival are presently available in New Zealand. In this study, I trapped 98 feralferrets over a 22‐month period and taggedthem with both passive integrated transponders (PITs) and ear tags. The standard Jolly‐Seber model was used to evaluate their abundance and survival. The estimated density of ferrets ranged from 1.5 to 6.29 ferrets km‐2, and increased over the course of this study. Annual survival for all ferrets tagged averaged 51%, but the probability of survival between capture sessions ranged between 0.33 and 1.0. Ferret capture rates were highest during summer and autumn. This seasonal pattern was probably a result of changes in both ferret abundance and trappability. As ferrets mate in spring, changes in behaviours associated with mating may account for reduced trappability at this time. My results suggest that trapping programmes targeting ferrets in the months immediately before their breeding season are likely to be the most cost‐effective means to reduce their numbers. © 2002 Taylor and Francis Group, LLC.