Effects of a non-toxic bait application on birds Assessing the impacts of a proposed kiore eradication programme on Little Barrier Island DOC SCIENCE INTERNAL SERIES 175

T Greene, P Dilks
5 References 15 5 DOC Science Internal Series 175 A B S T R A C T The impacts of a proposed aerial toxin application to eradicate kiore (Rattus exulans) were investigated for a number of bird species. A non-toxic aerial bait drop using pyranine-dyed baits was carried out over a 30 ha area on the lower slopes of Little Barrier Island (Hauturu), Hauraki Gulf, New Zealand, in September 2003. Application methods were similar to those proposed for the eradication. Rat trapping indices and low bait
more » ... ices and low bait removal (3.6% of baits removed over six nights) during the period of the study suggested that the kiore population was extremely low at that time of year. Despite the negligible rate of bait removal and an additional slow rate of bait decomposition, only one bird of 105 captured showed any evidence of having eaten bait. This result, combined with evidence from previous studies, suggests that the medium-to long-term benefits to the bird population resident on Little Barrier Island (Hauturu) arising from kiore eradication, far outweigh any perceived risks.