Salvin’s albatross breeding success and phenology assessment

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Summary

Salvin’s albatross Thalassarche salvini are a Nationally Critical seabird endemic to New Zealand. They breed predominantly at the Bounty Islands (Sagar et al. 2015), and are one of the New Zealand seabird species most at risk from fisheries bycatch (Abraham & Thompson 2015; Richard & Abraham 2015).

The population status at the Bounty Islands is poorly known due to logistical difficulties in conducting research at this remote location, and differences and inherent uncertainties in methods previously used to assess population status (Taylor 2000; Baker et al. 2014; Sagar et al. 2015; Parker & Rexer-Huber 2020). Even basic breeding chronology—laying, hatching, and fledging dates, colony return dates—and metrics like productivity or breeding success remain poorly defined because of access difficulties. Only hatching dates have been recorded directly (i.e. observers being present), with laying date estimates all calculated back from hatching dates using incubation periods from other species (Robertson & van Tets 1982; Clark et al. 1998; Sagar et al. 2015).

The primary objective of this report is to describe aspects of Salvin’s albatross phenology. From time-lapse images taken over a year, we determine the following dates: when chicks fledge; when adults depart the colony at the end of the breeding season; and when adults return to the colony. We also record nest-level reproductive success from the time-lapse cameras and use these to model daily survival rates and estimate breeding success overall. A secondary objective is to evaluate whether similar phenology and breeding outcome data can be obtained from tracking data, using migration dates. Here we examine phenology and productivity findings, and make recommendations for future deployments of nest cameras to assess similar questions at other sites and/or other species.