Heard Island and McDonald Islands 🇭🇲

Heard spotted the island while sailing south of the Kerguelen Islands, named it after himself and claimed it for the United States, though Washington declined to endorse the claim. Earlier reported sightings in the 1830s and 1840s remain unverified, and no evidence of human presence before the 1850s has been found. The sighting opened the islands to commercial exploitation.

McDonald sighted the smaller island group a year after Heard's discovery and named them after himself. The naming completed European identification of the archipelago that would later form a single Australian external territory.

A party of sealers from the ship Corinthian landed on Heard Island, inaugurating decades of elephant seal hunting. Over the following decades more than 40 vessels made over 100 visits, with sealers digging rudimentary shelters into the ground as the island's first human-made structures.

Elephant seal blubber was rendered into oil on the island, peaking in 1859 when 24 vessels were stationed there. Most companies were American and based in New England, though Australian sealers such as James William Robinson, backed by Tasmanian merchant William Crowther in 1858, also participated. Fourteen ships were wrecked near the island and around 60 sealers died between 1857 and 1881.

The ship Challenger called at Heard Island in 1874 and Gauss followed in 1902, each remaining only a few hours and observing only the north-western side. These visits produced the earliest scientific records of the territory.

Intensive hunting exhausted the island's elephant seals, and sealing activity declined substantially by the 1880s. Fur seals were likely nearly or completely eradicated during the nineteenth century, recovering only in the twentieth. The collapse ended the islands' first economic role.

Britain formally asserted sovereignty over the islands, raising its flag in 1910 and again in 1929. Between 1910 and 1926 the British government issued licences for sealing and whaling, and in 1926 leased the islands to a British company, which had abandoned the lease by 1930.

One of the first conventional structures erected on Heard Island, the hut was built by whalers on behalf of the British Admiralty. It marked the shift from rudimentary sealers' shelters to permanent infrastructure.

Two scientific parties landed in 1929, one led by the Swiss geologist Aubert de la Rüe and the other from the British Australian and New Zealand Antarctic Research Expedition. Poor weather extended BANZARE's planned three-day stay to eight days. The British flag was also raised on the island that year.

London judged that Australian proximity would provide a firmer sovereignty claim over Antarctic sectors and reduce administrative complexity. After the 1933 transfer the Australian government began preparing to take possession of Heard Island and the McDonald Islands as well.

From a small number of breeding pairs recorded in 1947, king penguins on Heard Island reached more than 100,000 pairs by 2004. Antarctic fur seals also recovered, peaking near 30,000 in a 2000–2001 survey and growing about 10 percent annually.

Fourteen men of the Australian National Antarctic Research Expeditions landed on 11 December 1947, raised the Australian flag and built an observatory. Over 14 months they conducted weather observations, geological and wildlife surveys and mapping, reinforcing Australia's strategic and economic interests and laying foundations for a permanent Antarctic presence.

Total glacier area fell from an estimated 289.4 square kilometres in 1947 to 225.7 in 2019, with annual loss rates rising from 0.25 percent in 1947–1988 to 0.43 percent in 1988–2019. Stephenson Glacier's recession accelerated from 18 metres per year before 1987 to 100 metres per year to 2000, and Brown Glacier lost 38 percent of its volume by 2004. Average annual temperature rose about 0.8 °C between 1948–1954 and 1997–2005.

From 1950 ANARE parties bred and trained sled dogs at the Heard Island station. Many of these dogs went on to support Australian stations on the Antarctic continent, making the island a logistical staging point for continental operations.

On 19 December 1950 Britain and Australia exchanged notes transferring sovereignty over Heard Island and the McDonald Islands to Australia, with effect backdated to December 1947. Britain thereby handed these uninhabited, barren, sub-Antarctic islands in the southern Indian Ocean to Australia, giving it a sub-Antarctic external territory and an eventual vast maritime zone.

The Act established the legal framework and administrative mechanism for the newly acquired territory. It also empowers the Governor-General to issue ordinances for its administration.

The station, which had grown to about 25 buildings and hosted seven rotating ANARE parties each staying 12–14 months, was shut in 1955. Much of its equipment was transferred to the new Mawson Station on the Antarctic continent, shifting Australia's polar centre of gravity southwards.

Voyages in October 2025 and January 2026 carried out wildlife and vegetation surveys, removed over a tonne of waste and asbestos and installed remote ecosystem monitoring equipment. The visits also confirmed that H5 bird flu had reached the island.

A ten percent tariff was applied to Heard Island and McDonald Islands in April 2025. It was attributed to erroneous data showing 1.4 million US dollars of imports, largely machinery and electrical goods, from the territory in 2022.

Since May 2014 entry without authorisation has been banned, and all visitors must complete a training programme and comply with quarantine procedures. The rules protect the islands' biosecurity and wilderness status.

Australia claimed exclusive rights to seabed resources over 1,130,000 square kilometres surrounding Heard Island and McDonald Islands. The proclamation substantially enlarged the resource jurisdiction generated by the territory.

The treaty enabled joint surveillance and patrolling of the waters around Heard Island and McDonald Islands and the neighbouring French Kerguelen Islands. It strengthened enforcement against illegal fishing in the southern Indian Ocean.

Proposed in a commissioned 2000 report, the reserve was the world's largest marine protected area at the time and was designed to protect marine fauna and meet obligations under the Convention on Biological Diversity. Expanded in 2014 and 2025, it now covers about 380,000 square kilometres, roughly 90 percent of the Australian exclusive economic zone around the islands.

The 1999 Act became the main legislative framework for environmental conservation in the territory. It consolidated Australia's obligations towards the islands' ecosystems.

A vessel was arrested for illegal fishing around Heard and McDonald Islands for the first time in October 1997. By 2004 eight vessels had been arrested, seven with Australian Defence Force involvement, and illegal fishing was reportedly eliminated after 2006–2007.

Commercial fishing began in the territory's waters in 1997, targeting Patagonian toothfish. By the 2021–2022 season five vessels shared a maximum quota of 3000 tons, though spawning stock biomass had fallen to 45 percent of pre-exploitation levels by 2023.

Populated by large numbers of seal and bird species, the uninhabited islands were inscribed on the World Heritage List in 1997 and are protected as a marine and nature reserve.

Eruptions in 1992 and 1997 followed a long dormancy. During the 1990s volcanic activity raised the islands by nearly 100 metres and more than doubled the main island's size while stripping its vegetation; between 1994 and 2004 McDonald Island grew from about 1 to 2.5 square kilometres and joined Flat Island by an isthmus.

The island hosted an experiment investigating whether acoustic signals transmitted through the ocean could measure changes in ocean temperature. The test used the territory's remote position in the southern Indian Ocean for global-scale climate monitoring research.

The 1987 ordinance built on the 1953 Act to regulate activity and protect the islands' environment. It was followed by the first Heard Island Wilderness Reserve Management Plan in 1995.

The 2745-metre stratovolcano was first climbed in 1965, followed by the Anaconda expedition in 1983 and the Australian Army Alpine Association in 1999–2000. The ascents demonstrated the logistical reach of expeditions to the remote territory.

Visits by tourists and private expeditions to Heard Island have occurred since 1963. Two recorded successful human landings on the McDonald Islands took place in 1971 and 1980.

After the station closed, scientific presence was reduced to intermittent short visits. In 1992 one party wintered on the island for the first time since 1955.