A sensitivity analysis of Huttonʹs shearwater: prioritizing conservation research and management Original Research Article

Huttonʹs shearwater Puffinus huttoni is an endangered seabird that breeds at just two colonies, which are subject to predation from introduced mammals. Whether the remaining populations are stable is unknown. In order to help focus future research and management into key areas, we developed a population model of Huttonʹs shearwaters. The model incorporated environmental variation and also included uncertainty in the estimation of both the mean and the between-year variation of parameters. The sensitivity analysis indicated that the population growth rate of the model was most influenced by the values of mean adult survival, recruitment and the between-year variation in adult survival. In contrast, the model was relatively robust to variation in the mean and between-year variation of most breeding parameters. Future research would best be directed away from measuring breeding parameters alone and focused on determining causes of adult and juvenile mortality such as by-catch at sea and numbers of adults preyed upon by stoats (Mustela erminea). It is important to assess both average rates of mortality and between-year variation in this rate.