Inter-annual and inter-colony variability in breeding performance of four colonies of short-tailed shearwaters

Biotic responses to large-scale climate processes are scale-dependant and can influence population trajectories of highly migratory species such as short-tailed shearwaters Ardenna tenuirostris. In this study, we quantified changes in climate, measured through large-scale climate indices (i.e. Northern Pacific Index, Pacific Decadal Oscillation, El Nino-Southern Oscillation and Southern Annular Mode) and local weather conditions (i.e. rainfall) on the breeding performance of short-tailed shearwaters at four of their breeding colonies within the Furneaux Island Group, Tasmania, Australia, from 2010 to 2018. There was inter-colony variability in adult body mass and breeding participation, which were influenced by climate conditions in the preceding year. In contrast, breeding success was influenced by climate conditions in the preceding three to four months and by local weather conditions at the time of breeding. These findings demonstrate that variation in the breeding performance of short-tailed shearwaters are explained both by large-scale climate indices and local environmental conditions. The outcomes of this study provide a better understanding of the environmental factors affecting short-tailed shearwaters.

Automated summary

The study found that the breeding performance of short-tailed shearwaters is influenced by both large-scale climate indices and local environmental conditions. There is variability in adult body mass and breeding participation among different colonies, with these factors being affected by climate conditions in the previous year. Breeding success, on the other hand, is influenced by climate conditions in the preceding three to four months and local weather conditions during breeding.