- Sophie Thomas
2021: a mixed bag for Tristan albatrosses
Every year our Overwintering Team conduct their ‘round island’ count at this time to establish how many Tristan albatross chicks survived the winter to reach a size and age at which they are likely to go on and fledge (in December). This year the weather was too poor for the team to complete the check in one (three-day long) trip and so we were made to wait on tenterhooks for a few days longer than usual. But the numbers are now in and it is fair to say it is a mixed bag.
We always expected chicks would still be lost this year, but we hoped to be able to start baiting before the worst of the winter hardships hit the mice – and consequently, the albatross. During incubation and for the first couple of months of its life, Tristan albatross chicks have a parent close by at all times. At the end of this brood-guard phase, the parents are (largely) both away at sea, returning to provision the chick but not to stay with it. It is possible that albatross chicks are particularly vulnerable at this point, and on Gough this vulnerability is likely exacerbated as it coincides with the start of winter when food options for mice begin to run out.
Our team do two round island counts – one at the start of the year and one in Sept/Oct. But between those times, they also make regular (approximately monthly) checks at two colonies that are closer to home – Tafelkop and Gonydale. At these two colonies, no fresh mouse wounds were observed after the first baiting in the area and chick survival was high. The figures from these sites are amazing – 70.9% at Gonydale and an astonishing 92.9% at Tafelkop – far higher than we’ve recorded before.
But all in all, breeding success for this year across the whole island comes in at 39.7% - not much higher than last year’s 37.2%.
It is crucial to appreciate that this is NOT indicative of the outcome of the eradication operation – most likely merely a reflection of the point at which we were able to distribute bait combined with the end of the brood-guard phase. Importantly, high breeding success across the island would not have been indicative of success either – if mice are still present on the island, they are likely to be few in number and may not need to attack albatross chicks to survive. This is part of the reason why we won’t be able to ascertain whether the eradication attempt was successful for at least two years. Hopefully we will, however, be able to report on greatly improved Tristan albatross breeding success before then.
This year the RSPB and its partners have attempted to eradicate the house mice on Gough and make it a seabird paradise once again. The project was originally scheduled to go ahead in 2020, but the coronavirus pandemic meant the RSPB and the Tristan da Cunha government had to abandon these plans and airlift the team home. With the delays the project now has a significant funding deficit.
If you would like to help close this funding gap, you can donate directly to the restoration project at https://www.rspb.org.uk/join-and-donate/donate/appeals/gough-island/
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Acknowledgement The Gough Island Restoration Programme is being carried out by the RSPB in partnership with Tristan da Cunha, BirdLife South Africa, the Department of Forestry, Fisheries and the Environment (South Africa), the Royal Zoological Society of Scotland, Island Conservation, Conservación de Islas, Manaaki Whenua - Landcare Research and BirdLife International. The programme is part-funded by the RSPB, the UK Government, the National Fish and Wildlife Foundation and other generous individuals and organisations.