Guest Blog by Dr Alex Bond, RSPB Senior Conservation Scientist, The Centre for Conservation Science.

Deep in the South Atlantic Ocean, on a tiny island called Gough, thousands of kilometres from land, a disaster plays out each year – introduced mice attack Tristan Albatross chicks more than 100 times their size. 

Our paper Trends and tactics of mouse predation on Tristan Albatross Diomedea dabbenena chicks at Gough Island, South Atlantic Ocean with colleagues at the Percy FitzPatrick Institute of African Ornithology at the University of Cape Town, appeared online today in the open access journal Avian Conservation and Ecology, and documents how this grisly event unfolds.

A six week old Tristan Albatross chick is attacked by mice despite the parent being present at the nest. This chick died 3.3 days after the first mouse attack.

Albatross lay only one egg every other year, and on island without introduced predators, about 70% of pairs will successfully raise a chick – which takes almost an entire year!  But on Gough Island last year, less than 10% of Tristan Albatross pairs were successful.  We set out to see when and how these nests failed by placing remote video recorders and motion-activated cameras near 20 nests in 2014.

Tristan Albatross chicks are constantly tended by their parents for the first month, and the both parents range far over the South Atlantic in search of food for their nest-bound chick.  That’s when the problems really start.  After about a month of being left alone, the mice attack the albatross chicks.  Between one and nine mice target the chicks’ rump, and two-five days later, in the midst of the austral winter, the chicks die.

What happens next - Expedition to Gough

The situation is grim, and the solution is to restore Gough Island by eradicating the mice, which is easier said than done. 

The RSPB, Tristan Conservation Department, and Percy FitzPatrick Institute of African Ornithology at the University of Cape Town have been working towards the goal of mouse eradication for more than ten years, and this September will mark the 61st scientific expedition to Gough.

Bird monitoring and preparations for mouse eradication

We monitor several globally threatened and regionally important species, including Northern Rockhopper Penguin, Atlantic Yellow-nosed Albatross, Atlantic Petrel, and Great Shearwater, and this year we are beginning a study of the health of Gough’s two endemic landbirds – Gough Bunting and Gough Moorhen.  In any future eradication operation, it’s likely that these two species will need to be brought into captivity to minimize their exposure to rodent bait pellets, so understanding the normal condition of the birds, and identifying any naturally occurring parasites, diseases, or pathogens will make us better prepared for any eventuality. We’ve partnered with the Royal Zoological Society of Scotland, and together with the Tristan Conservation Department, we will undertake this study in September, supported financially by the RSPB and Defra.

We’ll also do the annual island-wide census of Tristan Albatross chicks, which hatched about a month ago, though the vast majority likely won’t make it that long.

Find out more about our work on Tristan da Cunha which has been supported by many funders including OTEP, Darwin, Darwin Plus, Defra, the European Union’s EDF-9 and ACAP and the work of our Albatross Task Force.