view of South Hill, Inaccessible.Inaccessible Island

Back in 1982, after a season as warden on the Isle of May, I was invited at a couple of days notice to join the Denstone Expedition to Inaccessible Island. One of the Tristan da Cunha group in the central south Atlantic, Inaccessible is one of the least man-modified temperate islands in the world. It is uninhabited, has no non-native vertebrates (cats and rats being the traditional culprits that have been introduced to islands and caused havoc with their native wildlife) and was relatively poorly studied. Inaccessible is home to millions of breeding seabirds, including a huge population of Great Shearwaters, and the endemic Spectacled Petrel, and four species of landbirds - two buntings, a thrush, and the world’s smallest flightless bird, the Inaccessible Rail (below, right) which weighs in at less than 50 grams.Inaccessible Rail

The Denstone Expedition, the brainchild of Mike Swales, was the first to map the island, and scientists of various disciplines, including volcanology and invertebrate zoology, were supported by former pupils of Denstone College in Staffordshire.

The expedition spent about four months on Inaccessible. During this time we got a fair idea of the island’s bird population, studied its buntings and the flightless rail for the first time in any detail, surveyed its seabird populations, and ringed over 3,000 birds.

Perhaps the most significant ornithological finding was that the Tristan Buntings on the island plateau were subtly different from those on its slopes and coastal forelands. Prompted by this discovery, subsequent work by Peter Ryan elucidated the taxonomy and ecology of the Nesospiza buntings. I was dead chuffed, to put it mildly, when in a reappraisal of their genetic relationships (Taxonomic and conservation implications of ecological speciation in Nesospiza buntings on Tristan da Cunha, Bird Conservation International, 2007. 18: 20-29), Peter named the Upland Inaccessible Bunting Nesospiza acunhae fraseri after me, as I had sort of discovered it.

The expedition spent Christmas on the main island of Tristan (below), as guests of the islanders. This was also a memorable experience, the inhabitants of the “loneliest isle” being fantastically hospitable and welcoming.

Tristan da CunhaOn the way back from Tristan I called in at the University of Cape Town and met some of the ornithologists at the Percy FitzPatrick Institute of African ornithology (affectionately known as the Fitztitute). Somehow, I wangled myself a post-grad project there, studying the effects of invasive alien plants on the birds of the fynbos shrublands. Thus started our love affair with the Cape and its wildlife (not to mention climate).

In 1993 I was able to visit Inaccessible briefly again. Greeting me on the beach was a Tristan Thrush (Starchy) that I had ringed a decade before. I then went on to Gough Island, 350 km to the south, and spent a few weeks there as environmental inspector of the South African weather station during the annual personnel changeover.

Gough is also relatively very unspoilt, all too rare nowadays, and has been described as the most important seabird island in the world. It also holds an endemic bunting, a flightless moorhen and almost the entire population of Tristan (Wandering) Albatross (there are a couple of pairs on Inaccessible; the entire population on Tristan was eaten by the islanders and their pigs soon after they settled there in 1816). Other seabirds include as many as 2 million pairs of Broad-billed Prion (below).

Accidentally introduced by visiting sealers in the nineteenth century, the House Mice on Gough have evolved into larger forms of their mainland ancestors and are now eating their way through the island’s population of seabirds and buntings. This has potentially catastrophic consequences for the birds, and the removal of the mice is surely a world conservation priority. If you don’t believe that mice can be a danger to birds as big as albatrosses, have a look at this video clip and this BBC report. Scary stuff.

Broad-billed Prions

 

Gough Met Station

 

 

The Tristan da Cunha Government and T da C Association website is the best source of information and current news from the islands. It's hard to believe that it is not so long ago that the island was receiving only a couple of visiting ships and mail deliveries each year, but now it is as technologically-advanced (if not more so) than anywhere else in the world. The islanders are now very proud and proprietorial of their seabirds and other wildlife, and the Tristan da Cunha group as a whole has a higher percentage of its land area protected as conservation areas than any other country in the world.