Tītī Islands weka and rat impact studies

Weka and rat impact studies on the Tītī Islands

Principal investigators: Professor Henrik Moller, Jamie Newman

Subcontractors: Henrik Moller, Jamie Newman

Staff involved: Sam McKechnie

Brief abstract

Our Kia Mau Te Tītī Mo Ake Tonu Atu research team banded an adult breeding sooty shearwater that was subsequently drowned in the Command Oil spill in the San Francisco Bay in 1999. The tanker owners were sued and a fund established for reparation payments. Our simulations suggested that around 14,000 adults were drowned by the spill, but it may have been as many as 32,000. Certainly it was the species most impacted by the spill, so the case for cultural damages was compelling.

We wrote an application on behalf of the Rakiura Maori community for funds to eradicate rats and weka (introduced predators of tītī eggs and chicks) from four tītī breeding islands in order to repair the oil spill injury. They were granted approximately NZ $620,000 for eradication, quarantine and monitoring island restoration following the project. This subcontract established a set of BACI ('Before-After-Control-Impact') plots where tītī density has been measured. Surges in tītī abundance are expected from 2014, once the newly protected cohorts of chicks return to breed on those islands where weka and rats have been eradicated.