A population and distributional study of white-capped albatross Auckland Islands 2008-09

Download the publication

POP 2005/02 - Annual report 2008/09 (PDF, 566K)

Summary

South West Cape, main Auckland Island, and Disappointment Island were visited during
November-December 2008 (incubation stage) by a three-person field team to continue studies into the at-sea distribution and demography of white-capped albatross.

GPS data-loggers provided locations from an additional seven foraging tracks undertaken by white-capped albatross from the South West Cape colony during the incubation stage of the breeding season. These data revealed that birds travelled extensively, crossing the Tasman Sea to an area off south-east Australia and utilising an area from eastern Foveaux Strait northwards to the east of South Island.

A total of 15 satellite transmitters (PTTs) were deployed on incubating birds at Disappointment Island, the main breeding site for white-capped albatross. These devices were expected to transmit location information for approximately 90 days, potentially covering the incubation, guard and the early part of post-guard chick rearing phases.

Overall, the at-sea distribution of birds from Disappointment Island during incubation was not markedly different from that of birds at South West Cape. During the guard stage, birds travelled less far from the colony, but then expanded their foraging range during the post-guard chick rearing stage.

Overlap between birds and fishing effort was most pronounced during March and April, with an area immediately to the north of the Auckland Islands being used by both birds and fishing vessels. Additionally, white-capped albatross during February (chick guard stage) in 2009 tended not to utilise an area to the east of the islands which was heavily used during the same period in 2006. We suggest this change in distribution was not due to a colony effect, but more likely reflected an environmental difference between years, supported by a corresponding shift in fishing effort away from the eastern area in 2009.

A total of ten geolocation loggers were retrieved from birds tagged as breeders in previous seasons, bringing the total retrieved to date to 23. Preliminary assessment of the location data from all 23 tags revealed that only 3 birds (13%) travelled to southern Africa during the non-breeding period, with 20 birds (87%) remaining within Australasia year-round.

Population studies continued with banding of additional breeding adults bringing the total of banded breeding birds within the study area to 119, and a total of 65 active and marked nests. Additionally, banding of potential recruits to the population within the study area continued, and ground-truthing work was undertaken in support of another aerial survey of the entire Auckland Islands population. Observations of breeding frequency, nest-site occupancy and inter-annual variation in population estimates continue to suggest that white-capped albatross is predominantly a biennially-breeding species.