The Territory of Heard Island and McDonald Islands is an Australian external territory in the southern Indian Ocean. Discovered in the mid-19th century, the territory is a group of sub-Antarctic volcanic islands that lie on the Kerguelen Plateau. It is about 4000 kilometres (2500 mi) south-west of the Australian mainland and 1700 kilometres (1100 mi) north of Antarctica. The territory contains Australia's only active volcanoes and is home to its highest point outside the Australian Antarctic Territory, Mawson Peak. The territory is uninhabited and has been described as one of the most remote places on Earth.
The first confirmed sightings of Heard Island and the McDonald Islands took place in the 1850s. Heard Island was occupied by sealers until 1882 and saw occasional scientific visits in the late 19th and early 20th centuries. The territory was claimed by the United Kingdom and was then transferred to Australia in 1947. Between 1947 and 1955, the Australian National Antarctic Research Expeditions (ANARE) occupied a research station on the island. Since the closure of the ANARE research station, the islands have been visited by occasional scientific and private expeditions. Today, the islands are a nature reserve and World Heritage Site managed by the Australian Antarctic Division.
Heard Island is dominated by Big Ben, a stratovolcano that is topped by the volcanic cone Mawson Peak. About 70 percent of the island is covered by year-round glaciers, while vegetation occupies just 5 percent. The island is volcanically active, with Mawson Peak regularly emitting steam and vapour and occasionally releasing flows of lava. The McDonald Islands, located about 43 kilometres (27 mi) to the west of Heard Island, are a group of smaller volcanic islands that have seen just two recorded human landings. Heard Island and the McDonald Islands are known for their harsh climate, characterised by cold temperatures, strong winds, and heavy rain and snow.
Heard Island and the McDonald Islands are home to a large number of eastern rockhopper, gentoo, macaroni, and king penguins. With more than one million breeding pairs, Heard Island contains about 20 percent of the world's macaroni penguins. The islands also contain substantial populations of elephant seals and Antarctic fur seals. They are a breeding site for at least 15 flying seabird species, including the Heard Island cormorant, a species unique to Heard Island. Commercial fishing of Patagonian toothfish and mackerel icefish takes place in the surrounding waters. Heard Island has seen rapid melting of its glaciers and other environmental changes in recent decades, largely due to climate change.
The first confirmed sighting of Heard Island took place in 1853 when the island was spotted by the American captain John Heard aboard Oriental. Other sailors had reported observing land south of the Kerguelen Islands during the 1830s and 1840s, but whether they in fact sighted Heard Island is unclear. Researchers have suggested that earlier sightings of the island may have been kept secret for commercial reasons, but no evidence has been found on the island of human inhabitation or visitation prior to the 1850s. Heard named the island Heard Island and claimed it for the United States, but the country's government declined to endorse the claim. In 1854 the British captain William McDonald sighted the McDonald Islands aboard Samarang; he likewise named the islands after himself. A party of sealers led by the American captain Erasmus Darwin Rogers of the ship Corinthian made the first recorded landing on Heard Island in 1855.
Sealers continued to occupy the island over the following decades, with more than 40 vessels collectively making over 100 visits to hunt elephant seals and process their blubber into oil. Between 1855 and 1880, more than 100,000 barrels of oil were produced on the island. At the peak of production in 1859, there were 24 vessels stationed at Heard Island. The majority of the sealing companies were American and were based out of ports in New England, although some of the sealers were from Cape Verde. The island was also exploited by Australian sealers, including James William Robinson, who conducted an expedition on behalf of the Tasmanian merchant William Crowther in 1858. Robinson wrote a memoir about the expedition, which is now held by the W. L. Crowther Library. During the sealing period 14 ships were wrecked near the island. According to one estimate, 30 sealers died on Heard Island between 1857 and 1881 and 30 died on their way to the island, largely after being washed overboard. By the 1880s the elephant seal population on the island had been severely depleted and sealing activity declined substantially.
Brief scientific expeditions to Heard Island took place in 1874, 1902, and 1929, with their observations limited to the north-western side of the island. The first two expeditions were undertaken by the ships Challenger and Gauss in 1874 and 1902 respectively; each remained at Heard Island for just a few hours. Two scientific parties landed on the island in 1929 and remained for eight days: one was led by the Swiss geologist Edgar Aubert de la Rüe, while the other was composed of members of the British Australian and New Zealand Antarctic Research Expedition (BANZARE) party. The BANZARE party had planned to spend just three days on the island, but were forced by poor weather to remain for an additional five days. Between 1907 and 1930, some sealing activity resumed on the island and whaling ships made occasional visits.
Heard Island and the McDonald Islands were claimed by the United Kingdom in 1908. The British flag was raised on Heard Island in 1910 and 1929, and between 1910 and 1926 the British government issued licences for sealing and whaling on the island. A British company was allowed to lease the islands from the British government in 1926, although by 1930 it was no longer exercising its lease. By the 1930s the British government felt that Australia's proximity to its Antarctic possessions would provide a firmer claim to sovereignty, particularly over sectors of the Antarctic continent, and would reduce the logistical complexity of administering the territories. After Britain's transfer of the Australian Antarctic Territory to Australia in 1933, the Australian government began preparing to also take possession of Heard Island and the McDonald Islands.
On 11 December 1947 a party of 14 men from the Australian National Antarctic Research Expeditions (ANARE), led by Stuart Campbell, landed at Atlas Cove on Heard Island and established a research station. The goal of the expedition was to establish an observatory on the island, reinforce Australia's strategic and economic interests in the territory, and lay the foundations for a permanent ANARE presence on the Antarctic continent. They raised the Australian flag and conducted weather observations, performed geological and wildlife surveys, and mapped the island over the next 14 months. The station was occupied until 1955 by a rotating series of seven ANARE parties, each of which spent 12–14 months on the island. On 19 December 1950 the territory was transferred from Britain to Australia via an exchange of notes, with the transfer backdated to December 1947. The Australian government passed the Heard Island and McDonald Islands Act in 1953 to establish a mechanism for the administration of its newly acquired territory.
The ANARE expedition parties operated a radio outpost and weather monitoring station on Heard Island and conducted research. Beginning in 1950 they also bred and trained sled dogs, many of which eventually supported Australian stations on the Antarctic continent. The ANARE station, which eventually grew to about 25 buildings, was closed in 1955 to fund the establishment of Mawson Station on the Antarctic continent. Much of the equipment on Heard Island was also transferred to Mawson Station.
Nineteen short research expeditions to the island took place between 1956 and 2004. In 1992, one of these expedition parties remained on the island over the winter for the first time since the closure of the ANARE station in 1955. Infrequent visits by tourists and private expeditions have also taken place since 1963. The island was the site of the 1991 Heard Island feasibility test, which investigated whether transmission of acoustic signals through the ocean could be used to study changes in ocean temperatures. The islands were inscribed on the World Heritage List in 1997. In the same year, the Australian ship Austral Leader began commercial fishing in the surrounding waters.