What Limits the Number of Tītī (Puffinus griseus) Harvested by Rakiura Māori?

Māori continue a centuries old harvest of tītī chicks (sooty shearwater, Puffinus griseus) on islands adjacent to Rakiura (Stewart Island). This study measured time limits on the number of Tītī taken each day from Putauhinu Island. In the first period of the harvest ("nanao") the chicks are extracted from the breeding burrows during daytime. In the second period of harvest ("rama") the chicks are caught at night after they have emerged from their nesting burrows. Capture rate is much higher during the rama than the nanao. More time is spent processing (plucking, cutting-up, gutting, and packing) chicks during rama than the nanao because of a 1.3-1.7 increase in the number of chicks caught. Recently introduced motorized plucking machines decrease the time required to pluck each chick and make plucking less physically demanding and less painful. However, motorized pluckers did not increase the number of chicks harvested on Putauhinu. Other social limits may control harvest intensity and influence sustainability of muttonbirding.