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POP2022-08 Adams Island seabird survey (Fairchild's Garden) - February 2025 (PDF, 2,560K)
Summary
Gibson's wandering albatross
Gibson’s wandering albatross (Diomedea antipodensis gibsoni) have been in decline since 2005. Research into the causes of and solutions to the falling numbers of Gibson’s albatross includes an annual visit to the main breeding grounds on Adams Island and this report describes the results of the 2025 breeding season. Breeding success in 2024 was 46%, the lowest for 8 years, with only 37 chicks produced from the study colony. The number of pairs nesting in three representative census blocks in 2025 was close to the average of the last ten years, with the poor breeding season in 2024 probably a “blip” rather than the start of a steep decline. Survival of both males and females has improved though confidence intervals around the most recent estimates are so large the level of improvement is not yet clear.
Satellite transmitters taped to the back feathers of 29 adult Gibson’s wandering albatross in January 2022 remained attached for an average of 179 days and those attached in January 2024 to 20 adults for 251 days, providing detailed information on patterns of use of the Tasman Sea. A combined total 10,204 days of tracking was recorded from even numbers of adult males and females, 19 of which were not-breeding and 30 of which were. One breeding female was almost certainly caught in June 2024 in the mid Tasman Sea by a longliner flagged to Chinese Taipei. Given the limited number of birds with transmitters and days tracked, this capture suggests an annual mortality rate of adults in fisheries interactions of 3.5% in the two years. Sixteen Gibson’s wandering albatross chicks about to fledge from Adams Island were fitted with satellite transmitters in late December 2024 and their movements will be followed throughout 2025.
In January 2024 and January 2025 aerial photographs were taken using drones of the entire breeding grounds of Gibson’s albatross on Adams Island. All 4,000ha of albatross nesting habitat was photographed across the two seasons, and 24% was photographed in both years. Orthomosaic images were constructed from the photos and the number of albatrosses on the ground in the orthomosaics were counted. Ground calibration checks undertaken at the same time as the photographs were used to provide correction factors of the proportion of birds on the ground which had eggs (has-egg rate; mean was 54% in 2024 and 67% in 2025). Another correction was made for the likely proportion of eggs not yet laid or nests that had failed at the time the photographs were taken. This lay-fail correction was derived from regular visits to the study area. The two corrections were applied to the number of birds counted from the drone imagery on Adams Island in 2024 and 2025. To estimate each year’s whole island number of breeding pairs, a growth-rate estimate from blocks counted both years was applied to blocks only counted in one year. The mean of the two year’s estimates was 4,497 breeding pairs. This is the first time since 1997 the number of breeding pairs nesting on Adams Island have been comprehensively assessed across the island. The proportion nesting in annual count blocks in 2024 (9.2%) and 2025 (9.7%) are similar to that recorded in 1997 (10.7%), indicating that the annual count blocks remain representative of whole-island trends in nest numbers. Compared to the ground counts undertaken in 1997, the drone-based estimates provided better coverage as drones could easily go everywhere but nesting birds couldn’t be distinguished from other birds on the ground from drone imagery. Therefore, the number of nesting birds is estimated not counted. In contrast, counts undertaken on foot can easily miss birds either obscured by vegetation or in places that are too difficult to walk, but the number of nesting birds is counted not estimated. It is not possible to objectively judge which method is better, but the drone estimates are easier.
Adams Island seabird survey
The planned field trip to Disappointment Island was prevented by poor sea conditions on arrival at the Auckland Islands, not allowing the field team to be landed to conduct the original work programme. An alternative back-up study site was identified on Adams Island which might allow access to the white-capped albatross colony at Logan Point. An inspection of that colony location from safe vantage points high up on Logan Point revealed very few accessible birds on the ground above the sheer sea cliffs. No obvious and safe access paths down to this colony could be determined without the use of contemporary aerial photographs. Unpublished photos showing the location of the main Logan Point colony from 2016 have been obtained from Barry Baker and are appended to this report for future use.
In addition to the attempted White-capped Albatross work, further seabird work relevant to the wider CSP medium term research plan – seabirds was completed, including, checking nests of white-chinned petrels at Fairchild’s Garden and applying a satellite tracking tag to this this species; monitoring northern giant petrel chicks close to fledging and applying satellite tracking tags; surveying light-mantled sooty albatross and applying satellite tags to accessible birds; and finally carrying out bird handling and banding training on Gibson’s albatross for DOC staff who will do future albatross monitoring work in the subantarctic.
A sample of breeding white-chinned petrels were banded by the field team further adding to the demographic dataset, but none of the previously marked birds could be located within the former study colony. A satellite tag was attached to a breeding female. This showed the bird made extensive use of the southern Tasman Sea and the seas off Tasmania providing detailed and novel, and highly detailed insights into this highly bycaught species, even if based on a small sample size. After rearing the chick, the female migrated east across the Pacific Ocean to the seas off Peru. Five fully-grown northern giant petrel chicks found near the campsite had satellite trackers attached. All these birds fledged in early February and flew north or east of the colony adding to the limited spatial insights into this species. However, most tags did not last more than three weeks. Yet, one bird had a reliable signal recorded from the South Atlantic Ocean after quite a gap in transmission. This shows that some New Zealand giant petrels do leave the South Pacific and reach other ocean basins. There appears to be either high tag loss in this species or poor fledgling survival. Satellite tags were also attached to a pair of accessible non-breeding light-mantled sooty albatross. Both birds made regular trips south to the coast of Antarctica, and into the pack ice zone, before returning at intervals to Adams Island for courtship behaviour. Thirteen breeding and non-breeding Gibsons Albatrosses were captured and banded on the slopes above Fairchild’s Garden, And swab samples were taken for HPAI screening.
Publication information
Elliott G, Walker K, Rexer-Huber K, Tinnemans J, Anja McDonald, Tristan Rawlence, Parker, G. 2025. Gibson’s wandering albatross: drone-based population estimate, demography and at-sea distribution. Report prepared for Conservation Services Programe, Department of Conservation. 33 p.
Taylor G, Sagar R and Osborne J. 2025. Adams Islands seabird survey (Fairchild’s Garden) – February 2025. Report prepared for Conservation Services Programe, Department of Conservation. 20 p.