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Seabird research on the “Albatross Islands” of the Chatham Islands, Aug-Dec 2025. (PDF, 4,057K)

Summary

The Chatham Islands are a seabird biodiversity hotspot. A total of 21 Procellariidae species have  been recorded breeding in the archipelago, including 4 endemic species, and a further 2 species having >99% of their global population breeding in the group. Central to this hotspot are the “Albatross Islands” of the Chathams. Three scattered motu, which are the most distant islands in the Chathams group; Rangitutahi (The Sisters) is the most northern islet, Motuhara (The Forty Fours) the most eastern, and Te Tara Koi Koia (The Pyramid) the southernmost. These motu support the entire global breeding population of Chatham Island Mollymawk (Thalassarche eremita) and Pyramid Prion (Pachyptila pyramidalis); along with >99% of Northern Royal Albatross (Diomedea sanfordi) and Northern Buller’s Mollymawk (Thalassarche bulleri platei). In addition, they support Aotearoa’s largest population of Northern Giant Petrel (Macronectes halli).

Visits to all the three “Albatross Islands” in the Chathams was conducted in mid to late 2025 to undertake a range a research objectives. 

Three separate research visits are covered in this report. The first and third research visit, to Rangitutahi and Motuhara, respectively, were short trip’s part funded by the Department of Conservation directly, outside of the Conservation Services Programme (CSP). Each with a range of objectives revolving around obtaining abundance and tracking information on the key species characteristic of these islands (Northern Royal Albatross, Northern Buller’s Albatross, Northern Giant Petrel with additional work on Cape Petrel (Daption capense) and Pyramid Prion while continuing building up capture-resight data. The second research visit, however, to Tara Koi Koia, was funded through CSP (POP2025-07) with the following explicit objectives for Chatham Albatross:

1. To provide an updated population estimate
2. To update the at-sea distribution
3. To provide the first breeding success estimate, and potentially the first estimate of breeding probability
4. To contribute to the demographic dataset to enable estimates of adult survival

To increase efficiency, this report summaries the results of all three research trips. As with previous recent reports (e.g., Bell 2023, Bell 2024), this report provides a summary of the trip and the associated raw data (e.g., abundance and tracking data) with no specific specialised analyses of the data included. All these species are long-lived, and demographic data hasn’t been collected for enough years to warrant analyses capture-recapture/resight survival analyses yet.

Publication information

Bell, M. 2026. seabird research on the “Albatross Islands” of the Chatham Islands, Aug-Dec 2025. Conservation Services Programme report prepared  for the New Zealand  Department of Conservation. 20 p.