In between these two extremes – skirting the islands out of fear of an eruption and choosing an isolated existence on their shores – most Americans who viewed Amsterdam and St. Paul islands came in search of whales and fish. Even as some whalers and sealers confused the two islands, most knew how to find them, so distant from other land masses. By the time this map was made in 1856, merchants knew the route to China and Madras carried them past the islands.
Right whales proliferated in the waters around the islands in the warmer months of November and December. American whale ships would circle, the crews on board lowering their smaller boats when whale flukes were spotted (Journal of the Atlantic, 1835-7). The warm volcanic waters also attracted fish, ranging from small species to those reportedly weighing over forty pounds (Logbook of the George and Mary, 1850-2). Sailors in row boats could catch upwards of five hundred fish in a less than two hours, “all with the hook,” while paddling around the islands (Logbook of the Roscoe, Log 879, 1837-40).
The accumulation of knowledge about the islands drew more and more whalers to the isolated locales. By the middle of the century, over 300 people reportedly visited it in a year (Journal of the Atlantic, 1835-7). Eventually these were joined by a small community of settlers from the Mascarenes, perhaps two dozen in number by 1857 (Logbook of the Congress, 1857-9). These settlers and their animals had a growing impact on the wildlife of the islands. The visitors brought goats and hogs to live on the islands. They set fires that may have burnt much of the plant life.
Most seriously, they brought a small herd of cattle by the 1870s to live on Amsterdam. The settlers themselves left the island within a few decades but their cattle remained.
These voracious grazers, along with the settlers’ sheep and goats, cleared the grass that had covered the hillsides of the volcanic island. Non-human migrants, which included earlier stowaways of rats, cats, and other animals, decimated the bird populations of the island. They finished what the first sealers had started: eliminating the endemic flora and fauna of Amsterdam and St. Paul.
Out of twenty-two birds endemic to Amsterdam Island, five are now extinct and two are endangered. By the early twentieth century, the Amsterdam Island Duck, an endemic flightless bird, along with several species of petrels, were no long present on the island (source). By the 1980s, only a few breeding pairs of the Amsterdam albatross remained (source) although their populations may be recovering (source). The fur seal population was severely diminished by the end of the nineteenth century, although there is still a small colony on the island.
Today the cattle population of Amsterdam Island, culled from several thousand in the twentieth century to only a few hundred now, represents the only known feral cattle herd in the world. Rather than remove the animals, they have been fenced into an enclosure where they continued to be studied by scientists (examples include: 1, 2).
Despite being colonized by foreign species and visited by lonely sealers and shipwrecked sailors in the nineteenth century, Amsterdam Island is once again uninhabited. Wild cattle wander Amsterdam Island, so far from other landmasses, and few people are even aware of this island’s existence, let alone it’s unique history.