Movement and diet of domestic cats on Stewart Island/Rakiura, New Zealand

Domestic cats (Felis catus) in Halfmoon Bay, Stewart Island/Rakiura, were tracked to assess the potential for incursions into native forest around the township, and into Rakiura National Park c. 5 km away. During February and April 2005, 15 and 4 radio-collared cats were tracked, respectively. During a six-month period, cat-owners logged prey brought home by 11 cats. Cats were at home >90% of the time. Of the six cats that left home, movements were small: home range was between 0.05 and 16.6 ha (100% minimum convex polygon). Four cats brought prey home, comprising rats (Rattus spp.; 67% of prey items), and birds (four species, one native; 33%). Cats sampled at Halfmoon Bay were unlikely to enter the national park; however, many locations were within native forest patches, indicating that native birds within Halfmoon Bay were vulnerable to predation. The high proportion of rats caught could have benefits for native species.