Telemetry reduces colony attendance by sooty shearwaters (Puffinus griseus)

Twenty four imitation satellite transmitters (ISTs) were attached to breeding sooty shearwater (Puffinus griseus) adults late in the 1998/99 breeding season at Taiaroa Head, Otago Peninsula, New Zealand. There was no evidence of any difference in mean weight, change in weight or measurements of adults, nor breeding success of birds carrying ISTs compared with non-treatment birds. However the probability of attending the colony on a given night was reduced to 26% of its initial value from early March to mid April in IST-carrying birds, but not at all amongst non-treatment birds. No difference in ensuing weight, size and emergence date of chicks was detected between treatment and control groups. The maximum recorded attachment duration for an IST using glue was 21 days. Harnesses may be needed for longer studies of foraging behaviour late in the breeding season. Satellite-tracking studies will over-estimate normal foraging trip lengths and possibly under-estimate the amount of food usually provided to chicks if the reduced colony attendance detected in this study is a widespread problem.