These islands have a long history of successful yet interrupted pest eradication programmes. NZ Wildlife trapping records show that between December 1977 through to January 1982 it was determined that a fairly high population of rats existed on Tawhitinui Island. The known pest infestation combined with the relative isolation and easy access to the Tennyson Inlet islands lead to some of NZs earliest rat eradication programmes - Awaiti Island in 1982 and Tawhitinui Island in 1983/84. Possums were eradicated by DOC from Tarakaipa Island in 1995. Between the mid 1995s and 2005 DOC maintained “motel” bait stations on the Islands. These were irregularly checked. In 2005 another large eradication programme was launched by DOC on Tawhitinui and Awaiti Islands.
The likely pathway is that rodents swim from the mainland across to Tawhitinui Island (approx. 350 metres) at low tide. From this island they can then swim the 200 metres across to Awaiti Island. The 800 odd metres from Awaiti to Tarakaipai Islands and the 1.4 kilometres from Tarakaipai Island to the mainland is probably the reason there are few rats on this island but this distance can be swum by stoats.
What this history has taught us is that the reduction of pests on these islands will be an ongoing battle and our eradication programme needs to be specifically targeted to address this continual repopulating from the adjacent mainland.