Population Changes and Biology of the Wandering Albatross Diomedea exulans gibsoni at the Auckland Islands

Abstract

Summary: Diomedea exulans gibsoni is endemic to the Auckland Islands in the New Zealand subantarctic. In 1991, a program of regular census and population study was initiated to assess the impact of long-line fisheries by-catch on the status of the subspecies. This paper reports on field work carried out on Adams Island in the Aucklands group during January and February in most years between 1991 and 1997. Over this seven-year period, the average annual number of pairs nesting on Adams Island was 5831. This is the first reliable estimate of the size of the population. Evidence of population changes on the Auckland Islands is reviewed. Annual adult survival has been estimated for three years and averaged 97%; females have a 2% lower rate than males. D. e. gibsoni were easily sexed by measurements. Productivity over five breeding seasons averaged 67%. Timing of egg laying and nest site fidelity of D. e. gibsoni are described and compared with those of other subspecies of Wandering Albatross.