View source for Heard Island and McDonald Islands

{{Short description|External territory of Australia}}
{{Use Australian English|date=January 2012}}
{{Use dmy dates|date=April 2025}}
{{Infobox islands
| name               = Territory of {{nowrap|Heard Island and McDonald Islands}}
| image              = Flag of Australia (converted).svg
| image_caption      = [[Flag of Australia]], used for Heard Island and McDonald Islands<ref>{{Cite web |date=2 September 2022 |title=The symbols of other territories of Australia |url=https://www.pmc.gov.au/resources/australian-symbols-booklet/state-and-territory-symbols/symbols-other-territories-australia |archive-url=https://archive.today/20241010201659/https://www.pmc.gov.au/resources/australian-symbols-booklet/state-and-territory-symbols/symbols-other-territories-australia |archive-date=10 October 2024 |publisher=[[Australian Government]] |access-date=10 October 2024 |website=www.pmc.gov.au |language=en}}</ref>
| map_image          = Australia in its region (Heard Island and McDonald Islands special).svg
| map_caption        = 
| location           = Indian Ocean
| total_islands      = 
| major_islands      = 2
| area_km2           = 368
| highest_mount      = [[Mawson Peak]]
| elevation_m        = 2745
| population         = 0
| country            = {{flag|Australia}}
| timezone1          = [[UTC+05:00]]
| postal_code_type   = [[Postcodes in Australia|Postcode]]
| postal_code        = 7151
| iso_code           = [[ISO 3166-2:HM|HM]]<ref name="ISO3166">{{cite web |url= https://www.iso.org/obp/ui/#iso:code:3166:HM |title= Heard Island and McDonald Islands |date= 26 November 2018 |publisher= ISO}}</ref>
| module             = {{Infobox UNESCO World Heritage Site
 |child    = yes
 |ID       = 577
 |Criteria = Natural: viii, ix
 |Year     = 1997
 |Area     = {{cvt|658,903|ha}}
}}
| website            = 
}}

The '''Territory of Heard Island and McDonald Islands'''<ref name="CIA World Factbook">{{Cite CIA World Factbook|country=Heard Island and McDonald Islands|access-date=4 January 2009}}</ref><ref>{{cite web|author = UNESCO|title = Heard and McDonald Islands|url = https://whc.unesco.org/en/list/577|access-date = 31 January 2015}}</ref> ('''HIMI'''<ref name="abbr">{{cite web|author=Commonwealth of Australia |title=About Heard Island – Human Activities |url=http://www.heardisland.aq/about/human_activities.html |access-date=21 October 2006 |url-status=dead |archive-url=https://web.archive.org/web/20061018120534/http://www.heardisland.aq/about/human_activities.html |archive-date=18 October 2006}}</ref>) is an Australian [[States and territories of Australia|external territory]] comprising a [[volcanic group]] of mostly barren Antarctic islands, about two-thirds of the way from [[Madagascar]] to Antarctica. The group's overall land area is {{convert|372|km2|sqmi|0|abbr=on}} and it has {{convert|101.9|km|mi|0|abbr=on}} of coastline. Discovered in the mid-19th century, the islands lie on the [[Kerguelen Plateau]] in the southern Indian Ocean and have been an Australian territory since 1947.<ref>{{Cite web |date=9 July 2024 |title=Heard Island and McDonald Islands |url=https://www.antarctica.gov.au/antarctic-operations/stations/other-locations/heard-island/ |access-date=24 April 2025 |website=[[Australian Antarctic Program]] |language=en}}</ref><ref>{{Cite EBO |date=12 April 2025 |title=Heard Island and McDonald Islands |url=https://www.britannica.com/place/Heard-and-McDonald-Islands |access-date=24 April 2025}}</ref>

Heard Island and McDonald Islands contain Australia's only two active volcanoes. The summit of one, [[Mawson Peak]], is higher than any mountain in all other Australian states, territories or [[land claim|claimed territories]], except [[Dome Argus]], [[Mount McClintock]] and [[Mount Menzies]] in the [[Australian Antarctic Territory]]. This Antarctic territory is a land claim unrecognised by most other countries,<ref name="auto">{{Cite web|title = Antarctic Region|url = https://www.state.gov/key-topics-office-of-ocean-and-polar-affairs/antarctic/#:~:text=Seven%20countries%20(Argentina%2C%20Australia%2C,has%20not%20made%20a%20claim.|website = U.S. Department of State|access-date = 14 June 2024|language = en-AU}}</ref> meaning that Mawson Peak is the highest mountain with undisputed Australian [[Westphalian sovereignty|sovereignty]].

The islands are among the [[Extreme points of Earth#Remoteness|most remote places on Earth]]: They are located about {{convert|4100|km|mi nmi|abbr=off}} southwest of [[Perth]],<ref name="ga">{{cite web |url=http://www.ga.gov.au/bin/distancedraw2?rec1=293571&placename=Perth&placetype=0&state=0&place1=HEARD+ISLAND&place1long=73.532112&place1lat=-53.099331 |archive-url=https://web.archive.org/web/20081224215802/http://www.ga.gov.au/bin/distancedraw2?rec1=293571&placename=Perth&placetype=0&state=0&place1=HEARD+ISLAND&place1long=73.532112&place1lat=-53.099331 |archive-date=24 December 2008 |url-status=dead |title=Cocky Flies, Geoscience Australia |access-date=29 March 2016}}</ref> {{convert|3,850|km|mi nmi|abbr=on}} southwest of [[Cape Leeuwin]], Australia, {{convert|4,200|km|mi nmi|abbr=on}} southeast of [[South Africa]], {{convert|3,830|km|mi nmi|abbr=on}} southeast of [[Madagascar]], {{convert|1,630|km|mi nmi|abbr=on}} north of Antarctica, and {{convert|450|km|mi nmi|abbr=on}} southeast of the [[Kerguelen Islands]] (part of [[French Southern and Antarctic Lands]]).<ref name="distancefromto">{{cite web|url=http://www.distancefromto.net/ |title=Distance Between Cities Places On Map Distance Calculator |publisher=distancefromto.net|access-date=29 March 2016}}</ref>

The islands, which are uninhabited, can be reached only by sea, and typically require a two-week voyage from Australia to visit.<ref>{{Cite web|url=http://heardisland.antarctica.gov.au/about/frequently-asked-questions|title=Frequently asked questions|date=28 February 2005}}</ref>

==History==
===Early activities===
[[File:FMIB 46007 Antarctic Sea-Elephant Fishery.jpeg|thumb|Heard Island 1887 by [[Henry Wood Elliott]]<ref>Goode, George Brown (1887) Fisheries and Fishery Industries of the United States, (Washington, DC: Government Printing Office, 1887).</ref>]]
An early sighting of Heard Island is attributed to Peter Kemp of the British sealing [[Snow (ship)|snow]] ''Magnet'' on 27 November 1833.{{sfn|Downes|2002|p=5}} However, the evidence that Heard Island was the land sighted by Kemp is limited.{{sfn|Downes|2002|pp=8–9}} [[Kemp Land]] in Antarctica was later named in his honour.{{sfn|Downes|2002|p=7}}

An American sailor, John Heard, on the ship ''Oriental'', sighted Heard Island on 25 November 1853, en route from [[Boston]] to [[Melbourne]]. He reported the discovery one month later and had the island named after him.<ref name=":1" /> His wife [[Fidelia Heard]] provided the first written description and drawings of the island.<ref name=":02">{{Cite web |title=Fidelia Isthmus |url=https://data.aad.gov.au/aadc/gaz/display_name.cfm?gaz_id=139196 |access-date=11 April 2023 |website=Australian Antarctic Gazetteer}}</ref><ref>{{Cite web |last=Woehler |first=Eric |date=Spring 2004 |title=Heard Island: a history of exploration |url=https://www.antarctica.gov.au/magazine/issue-7-spring-2004/feature/heard-island-a-history-of-exploration/ |access-date=11 April 2023 |website=Australian Antarctic Magazine |via=[[Australian Antarctic Program]] |language=en}}</ref> William McDonald aboard ''Samarang'' [[1854 in Australia#Exploration and settlement|discovered the nearby McDonald Islands]] six weeks later, on 4 January 1854.<ref name=":1">{{Cite book | url=https://books.google.com/books?id=PYdBH4dOOM4C&q=heard+island&pg=PA342 | title=Exploring Polar Frontiers: A Historical Encyclopedia| isbn=9781576074220| last1=Mills| first1=William James| year=2003| publisher=Bloomsbury Academic}}</ref>

No landing took place on the islands until March 1855, when American sealers from ''Corinthian'', led by [[Erasmus Darwin Rogers]], went ashore at a place called ''Oil Barrel Point''. From 1855 to 1882 a number of other American sealers spent a year or more on the island, living in appalling conditions in dark smelly huts, also at Oil Barrel Point.<ref name=abc/> The island was also exploited by Australian sealers, including [[James William Robinson (sailor)|James William Robinson]]'s 1858 expedition on behalf of Tasmanian merchant [[William Crowther (Australian politician)|William Crowther]]. Robinson's memoir of the expedition was deposited in the [[W. L. Crowther Library]] and provides one of the most detailed accounts of early conditions on the island.{{sfn|McGowan|2000|p=62}} At its peak the community consisted of 200 people. By 1877, sealers had wiped out most of the seal population and left the island. In all, the islands furnished more than {{convert|100,000|impbbl|e3m3 e6USgal|order=out|abbr=off}} of [[elephant seal]] oil during this period.<ref name=abc>{{Cite news |last=McCarthy |first=Marty |date=25 January 2019 |title=Australia's mysterious land of fire and ice holds the secrets to Earth's past and future |url=https://www.abc.net.au/news/2019-01-25/heard-island-australias-mysterious-land-of-fire-and-ice/10713860 |url-status=live |archive-url=https://web.archive.org/web/20190125122356/https://www.abc.net.au/news/2019-01-25/heard-island-australias-mysterious-land-of-fire-and-ice/10713860 |archive-date=25 January 2019 |access-date=3 April 2025 |work=[[ABC News (Australia)|ABC News]] |language=en-AU}}</ref>

A number of wrecks have occurred in the vicinity of the islands. There is also an abandoned building left from John Heard's sealing station that is situated near Atlas Cove.<ref>{{cite web |url=https://www.antarctica.gov.au/news/2018/sealers-shipwrecks-and-survivors-inspire-new-names-on-sub-antarctic-island/ |title=Sealers, shipwrecks and survivors inspire new names on sub-Antarctic island |website=[[Australian Antarctic Program]] |year=2018}}</ref> The shipwrecked crew of ''Trinity'' spent 15 months on Heard Island from the wreck in October 1880 until their rescue in January 1882.{{sfn|McGowan|2000|p=68}}

In April 1910, the Australian-chartered steamer ''Wakefield'' briefly visited Heard Island as part of an unsuccessful search for {{ship|SS|Waratah||6}}, which had disappeared in July 1909 en route from Australia to England.<ref>{{Cite news|url=https://trove.nla.gov.au/newspaper/article/15155673|title=The Waratah: Wakefield's Cruise|newspaper=The Sydney Morning Herald|date=27 April 1910}}</ref> In June 1910, a party from the whaling vessel ''Mangoro'' annexed Heard Island on behalf of the United Kingdom. The annexation was protested by the French consul in [[Durban]], South Africa, on the grounds that the island was French territory.<ref>{{cite news|url=https://trove.nla.gov.au/newspaper/article/149154452|title=Latest British Annexation|newspaper=Geelong Advertiser|date=10 June 1910}}</ref>

The Kerguelen Whaling and Sealing Company, a South African enterprise, resumed sealing at Heard Island during the 1920s. Around this time the [[British Admiralty]] commissioned sealers to build a small wooden hut at Atlas Cove.{{sfn|McGowan|2000|p=62}}

===Australian administration===
[[File:Group Captain S.A. Campbell (centre) officially opening the first Australian Post Office to be set up in Antarctica. Assistant is L. Macey, Coogee, New South Wales, Chief Radio Operator at Heard (6433727833).jpg|thumb|The Heard Island Post and Telegraph Office, c. 1950]]
In November 1947, the [[Chifley government]] announced a series of [[Australian National Antarctic Research Expeditions]] under the command of [[Stuart Campbell (explorer)|Stuart Campbell]], a former [[Royal Australian Air Force]] officer. Prime Minister [[Ben Chifley]] announced that the expeditions would establish weather stations on Heard Island and [[Macquarie Island]], as well as a reserve fuel base on the French territory of [[Kerguelen Island]], as part of a scheme to establish a permanent Australian base in Antarctica.<ref>{{cite news|url=https://trove.nla.gov.au/newspaper/article/18049016|title=Antarctic Plans: Three Bases|newspaper=The Sydney Morning Herald|date=7 November 1947}}</ref>

Campbell's expedition landed at Atlas Cove on 17 December 1947, establishing a forward base for 14 scientists.<ref>{{cite news|url=https://trove.nla.gov.au/newspaper/article/18054676|title=Expedition Landing: Island Base in Antarctic|newspaper=The Sydney Morning Herald|date=22 December 1947}}</ref> Following the successful landing of all stores and equipment, a flag-raising ceremony was held on 29 December 1947.<ref>{{cite news|url=https://trove.nla.gov.au/newspaper/article/18055471|title=Landing On Island: All Stores, Men Ashore|newspaper=The Sydney Morning Herald|date=29 December 1947}}</ref> In response, the [[U.S. Department of State]] issued a statement on 4 January 1948 that it did not recognise an Australian claim to the island, as it considered it to be an Antarctic territory and did not recognise any claims from other sovereign states over the Antarctic.<ref>{{cite news|url=https://trove.nla.gov.au/newspaper/article/206887924|title=U.S.A Interest in Heard Island|newspaper=The Age|date=5 January 1948}}</ref>

In February 1951, the Australian government announced that it had received confirmation from the British government that it had relinquished any prior claim over Heard Island and the McDonald Islands, backdated to 26 December 1947.<ref>{{cite news|url=https://trove.nla.gov.au/newspaper/article/48183414|title=Territorial Acquisition: Australian Rights At Heard Island|newspaper=The West Australian|date=10 February 1951}}</ref>

Australians continuously occupied a station at Atlas Cove from 1947 to 1955. The first of these ventures arrived in December 1947 and stayed until February 1949.<ref>{{Cite book|last=Scholes|first=Arthur|title=Fourteen Men, the story of the Australian Antarctic Expedition to Heard Island.|publisher=E. P. Dutton and Sons|year=1951}}</ref> Two members of the 1952 wintering party died in May while returning to their hut: radio operator Richard James Hoseason was swept out to sea, while dog trainer Alastair Graham Forbes was rescued from the sea but died while attempting to return to the base.<ref>{{Cite book|last=Brown|first=Peter Lancaster|title=Twelve Came Back|publisher=Robert Hale Limited|year=1957}}</ref><ref>{{cite web|title=Tragic Deaths on Heard Island|work=Advocate |url=https://trove.nla.gov.au/newspaper/article/69461631|date=30 May 1952}}</ref> The camp at Atlas Cove was again occupied by American scientists in 1969 and expanded in 1971 by French scientists. Another station was established in 1971 at Williams Bay on McDonald Island in the [[McDonald Islands]].<ref>{{cite web|url=https://travelnoire.com/heard-and-mcdonald-islands|title=What Are The Heard Island And McDonald Islands?|access-date=7 April 2025}}</ref> Later expeditions used a temporary base at [[Spit Bay]] in the east, such as in 1988, 1992–1993, and 2004–2005.{{citation needed|date=April 2025}}

There were at least five private expeditions to Heard Island between 1965 and 2000. Several [[amateur radio]] operators have visited Heard, often associated with scientific expeditions. The first activity there was in 1947 by Alan Campbell-Drury. Two amateur radio [[DXpedition]]s to the island took place in 1983 using the callsigns VK0HI (the ''Anaconda'' expedition)<ref name=":0">{{Cite book|last=Thornton|first=Meg|title=Heard Island Expedition|publisher=Spirit of Adventure Pty Ltd|year=1983|isbn=0959256806|pages=28–29}}</ref> and VK0JS and VK0NL (the ''Cheynes II'' expedition), with a further operation in January 1997 (VK0IR). The DXpedition in March 2016 (VK0EK) was organised by Cordell Expeditions,<ref>{{cite web|website=[[American Radio Relay League]]|title=Heard Island VK0EK DXpedition Team Has Arrived, Operation Hours Away|url=http://www.arrl.org/news/heard-island-vk0ek-dxpedition-team-has-arrived-operation-hours-away|date=22 March 2016}}</ref> and made over 75,000 radio contacts.{{citation needed|date=April 2025}} The first recorded aircraft landing on McDonald Island was made by Australian scientists Grahame Budd and Hugh Thelander on 12 February 1971, using a helicopter.<ref>{{cite web|url=http://www.cerchi.net/destinations/2002_sioe/sioe_himi.html|title=SIOE 2002: Heard I. & The McDonald Is|date=1 August 2009|archive-url=https://web.archive.org/web/20120426052000/http://www.cerchi.net/destinations/2002_sioe/sioe_himi.html|archive-date=26 April 2012|last=Cerchi|first=Dan|website=www.cerchi.net}}</ref><ref name="aad">{{cite web|url=http://data.aad.gov.au/aadc/gaz/display_name.cfm?gaz_id=2177 |archive-url=https://web.archive.org/web/20110406140708/http://data.aad.gov.au/aadc/gaz/display_name.cfm?gaz_id=2177 |archive-date=6 April 2011 |url-status=dead |title=Gazetteer – AADC Name Details – Australian Antarctic Data Centre |via=[[Internet Archive]]|access-date=29 March 2016|website=[[Australian Antarctic Data Centre]]}}</ref> The DX code for Heard Island is 111.<ref>{{Cite web |title=ARRL DXCC LIST CURRENT ENTITIES February 2022 |url=https://www.arrl.org/files/file/DXCC/2022_Current_Deleted.txt |website=www.arrl.org}}</ref>

Mawson Peak, atop [[Big Ben (Heard Island)|Big Ben]], was first climbed on 25 January 1965 by five members of the Southern Indian Ocean Expedition to Heard Island (sometimes referred to as the ''Patanela'' expedition).<ref>{{Cite book|last=Temple|first=Phillip|title=The Sea and the Snow|publisher=Cassell Australia|year=1966}}</ref> The second ascent was made by five members of the Heard Island Expedition 1983 (sometimes referred to as the ''Anaconda'' expedition).<ref name=":0" /> A helicopter landing was made at the summit by an [[Australian National Antarctic Research Expeditions]] (ANARE) team on 21 December 1986. An [[Australian Army]] team was successful in making the third ascent in 2000.

In 1991, the islands were the location for the [[Heard Island feasibility test]], an experiment in very long-distance transmission of low frequency sound through the ocean.<ref>{{Cite web|title = The Heard Island Feasibility Test|website = [[University of Washington]]|year = 2007|url = http://staff.washington.edu/dushaw/heard/experiment/}}</ref> The [[United States Navy]]-chartered motor vessels {{MV|Cory Chouest}} and {{MV|Amy Chouest||2}} transmitted signals which were detected as far away as both ocean coasts of the United States and Canada.<ref>{{Cite web|title = Heard Island Feasibility Test – reception map|website=University of Washington|year = 2007|url = http://staff.washington.edu/dushaw/heard/experiment/HIFTmapMawsonAnt.shtml}}</ref>

In 2025, the Australian icebreaker [[RSV Nuyina|RSV ''Nuyina'']] conducted the [[Australian Antarctic Program]]'s first dedicated environmental management visit to Heard Island in more than 20 years.<ref>{{Cite web |date=2025-08-04 |title=Australian Antarctic Program heads to Heard Island – Australian Antarctic Program (News 2025) |url=https://www.antarctica.gov.au/news/2025/australian-antarctic-program-heads-to-heard-island-for-the-first-time-in-decades/ |access-date=2025-10-29 |website=www.antarctica.gov.au |language=en}}</ref><ref>{{Cite web |date=2025-10-24 |title=Voyage 1 Update: Project groups head to Heard Island – Australian Antarctic Program (News 2025) |url=https://www.antarctica.gov.au/news/2025/voyage-one-update-project-groups-head-to-heard-island/ |access-date=2025-10-29 |website=www.antarctica.gov.au |language=en}}</ref>

==Administration, economy and defence==
[[File:Weather personnel at Heard Island ANARE Station releasing free hydrogen Radiosonde Balloon (6433880227).jpg|thumb|Weather station personnel at Heard Island ANARE Station releasing a free hydrogen Radiosonde Balloon ({{circa|1953–1957}})]]

The islands are a territory (Territory of Heard Island and McDonald Islands) of Australia administered from [[Hobart]] by the [[Australian Antarctic Division]] of the Australian [[Department of Climate Change, Energy, the Environment and Water]]. The administration of the territory is established in the ''Heard Island and McDonald Islands Act 1953'', which places it under the jurisdiction of the [[Supreme Court of the Australian Capital Territory]], with the non-criminal laws of the [[Australian Capital Territory]] and the criminal laws of [[Jervis Bay Territory]] applying to the Territory.<ref>{{cite web|title=Heard Island and McDonald Islands Act 1953| url=https://www.legislation.gov.au/Details/C2008C00326|website=Federal Register of Legislation| date=4 July 2008| publisher=Australian Government|access-date=7 May 2018}}</ref> The islands are contained within a {{convert|65000|km2|sqmi sqnmi|adj=on}} marine reserve and are primarily visited for research, meaning that there is no permanent human habitation.<ref name="CIA World Factbook" />

[[File:Heard2.jpg|thumb|A research station on Heard Island]]

With the end of [[Seal hunting|sealing]], the only exploited resource is fish; the Australian government allows limited fishing in the surrounding waters.<ref name="CIA World Factbook" />

There are no active military installations nor defence personnel on the islands. However, as part of Operation Resolute, the [[Royal Australian Navy]] (RAN) and [[Australian Border Force]] deploy {{sclass2|Cape|patrol boat|5}} and {{sclass|Armidale|patrol boat|0}} patrol boats to carry out civil maritime security operations in both Australian mainland and offshore territories including the Heard and McDonald Islands.<ref>{{cite web |url=https://www.defence.gov.au/operations/resolute |title=Operation Resolute |website=Australian Government – Defence |access-date=20 August 2023}}</ref> In part to carry out this mission, {{as of |2023|lc=y}}, the RAN's ''Armidale''-class boats are in the process of being replaced by larger {{sclass|Arafura|offshore patrol vessel|1}}s.<ref>{{cite web |url=https://www.navy.gov.au/fleet/ships-boats-craft/future/opv |title=Arafura Class OPV |website=Royal Australian Navy |access-date=20 August 2023}}</ref>

Despite the lack of population, the islands have been assigned the [[country code]] HM in [[ISO 3166-1]] ([[ISO 3166-2:HM]]), hence the Internet [[top-level domain]] [[.hm]]. The time zone of the islands is [[UTC+05:00|UTC+5]].<ref name="timegenie">{{cite web|url=http://www.timegenie.com/country.time/hm |title=Heard Island and McDonald Islands :: Time Zones |publisher=timegenie.com|access-date=29 March 2016}}</ref>

In April 2025, as part of a [[Tariffs in the second Trump administration#"Reciprocal" tariff policy|sweeping campaign of tariffs against its trading partners]], the US explicitly implemented a 10% [[tariff]] against the islands, despite the islands being uninhabited, earning the islands widespread media coverage.<ref name=":3">{{Cite news |date=2025-04-03 |title=Trump's tariffs target Heard Island and McDonald Islands, Australian territory inhabited by penguins |url=https://www.cbsnews.com/news/trump-tariffs-heard-mcdonald-island-norfolk-australia/ |access-date=2025-04-03 |website=[[CBS News]] |language=en-US}}</ref><ref name=":5">{{Cite news |last1=Pannett |first1=Rachel |last2=Masih |first2=Niha |last3=Schaul |first3=Kevin |last4=Nakashima |first4=Ellen |last5=Hudson |first5=John |date=2025-04-03 |title=Trump's tariffs hit even remote islands. One is mainly home to penguins. |url=https://www.washingtonpost.com/world/2025/04/03/trump-tariffs-islands-uninhabited-heard-mcdonald/ |access-date=2025-04-03 |newspaper=The Washington Post |language=en-US |issn=0190-8286}}</ref><ref name=":7">{{Cite news |url=https://www.theguardian.com/us-news/2025/apr/03/donald-trump-tariffs-antarctica-uninhabited-heard-mcdonald-islands |title='Nowhere on earth is safe': Trump imposes tariffs on uninhabited islands near Antarctica |first1=Kate |last1=Lyons |first2=Nick |last2=Evershed |date=3 April 2025 |newspaper=The Guardian}}</ref> The US claimed it had a [[trade deficit]] with the islands, an allegation that appeared to be calculated from incorrect trade data. An analysis of US import data and shipping records by ''[[The Guardian]]'' indicated some shipments were incorrectly labelled as coming from the remote islands instead of their correct countries of origin. According to export data from the [[World Bank]], the US imported {{USD|1.4{{nbsp}}million}} ({{AUD|2.23{{nbsp}}million|link=yes}}) of products from Heard Island and McDonald Islands in 2022, nearly all of which was "machinery and electrical" imports.<ref>{{Cite news |last1=Lyons |first1=Kate |last2=Evershed |first2=Nick |date=2025-04-04 |title=Not that Norfolk! Mislabelled shipments led to Trump tariffs on uninhabited islands and remote outposts with no US trade |url=https://www.theguardian.com/australia-news/2025/apr/04/revealed-how-trump-tariffs-slugged-norfolk-island-and-uninhabited-heard-and-mcdonald-islands |access-date=2025-04-04 |work=The Guardian |language=en-GB |issn=0261-3077}}</ref>

==Geography==
{{main|Geography of the Heard and McDonald Islands}}
{{See also|Heard Island glaciers}}
[[File:Orthographic projection centred over the Heard Islands 2.png|alt=|thumb|242px|Heard Island and McDonald Islands in the Southern Ocean]]
[[File:Heard Island and McDonald Islands map.png|thumb|right|A map of Heard Island and McDonald Islands]]
Heard Island, by far the largest of the group, is a {{convert|368|km2|sqmi|adj=on}} mountainous island covered by 41 [[glacier]]s;<ref>{{cite book|last1=Ken Green and Eric Woehler|title=Heard Island: Southern Ocean Sentinel|date=2006|publisher=Surrey Beatty & Sons|pages=28–51}}</ref> 80% of the island is covered with ice.<ref name="CIA World Factbook" /> The [[Big Ben (Heard Island)|Big Ben]] [[massif]] dominates the island: It has a maximum elevation of {{convert|2745|m|ft}} at [[Mawson Peak]], the historically active volcanic summit of Big Ben, to which the average ascent from shore is steeper than that for any island of comparable size or larger; [[List of islands by highest point|only seven smaller islands are steeper]]. A July 2000 satellite image from the [[University of Hawaiʻi]]'s Institute of [[Geophysics]] and [[Planetology]] (HIGP) Thermal Alert Team showed an active {{convert|2|km|mi|adj=mid|-long}} and {{convert|50|-|90|m|ft|adj=mid|-wide}} lava flow trending southwest from the summit of Big Ben.<ref>{{cite web |title=Landforms of Heard Is and McDonald Islands |url=https://www.antarctica.gov.au/antarctic-operations/stations/other-locations/heard-island/nature/landforms/#Geology |website=[[Australian Antarctic Program]] |access-date=3 April 2025 |language=en |date=3 July 2024}}</ref>

The much smaller and rocky [[McDonald Islands (volcano)|McDonald Islands]] are located {{convert|44|km|mi nmi}} to the west of Heard Island. They consist of McDonald Island ({{convert|186|m|ft|abbr=on|disp=or}} high), Flat Island ({{convert|55|m|ft|abbr=on|disp=or}} high) and [[Meyer Rock]] ({{convert|170|m|ft|abbr=on|disp=or}} high). They total approximately {{convert|2.5|km2|sqmi}} in area, where McDonald Island is {{convert|1.13|km2|sqmi}}. There is a small group of islets and rocks about {{convert|10|km|mi nmi|abbr=on}} north of Heard Island, consisting of Shag Islet, [[Sail Rock (Heard Island)|Sail Rock]], [[Morgan Island]], [[Drury Rock]], and Black Rock. They total about {{convert|1.1|km2|sqmi}} in area.
[[File:2023-05-10-00 00 2023-05-10-23 59 Sentinel-2 L1C Custom script(1).jpg|thumb|[[Sentinel-2]] wildfire visualization image showing thermal activity consistent with volcanic activity on Mawson peak, Heard Island]]
Mawson Peak and McDonald Island are the only two active volcanoes in Australian territory. Mawson Peak is also one of the highest Australian mountains (higher than [[Mount Kosciuszko]]). It is surpassed by [[Dome Argus]], [[Mount McClintock]] and [[Mount Menzies]] in the [[Australian Antarctic Territory]],<ref>{{cite web|url=http://www.ga.gov.au/education/geoscience-basics/landforms/highest-mountains.html|publisher=[[Geoscience Australia]]|title=Highest Mountains|access-date=2 February 2012}}</ref> a [[Territorial claims in Antarctica|territorial claim]] unrecognised by most other countries,<ref name="auto" /> meaning that Mawson Peak is the highest mountain over which Australia has true [[Westphalian sovereignty|sovereignty]]. Mawson Peak has erupted several times since 2013 and as recently as May 2023.<ref>{{Cite news |url=https://www.theguardian.com/australia-news/2023/may/30/big-ben-volcano-heard-island-near-antarctica-spewing-lava-captured-satellite-spewing-lava |title=Australian volcano near Antarctica captured on satellite spewing lava |first=Graham |last=Readfearn |date=30 May 2023 |newspaper=The Guardian}}</ref> An earlier eruption was filmed on 2 February 2016.<ref>[https://www.bbc.com/news/world-australia-35467131 Rare glimpse of erupting Australian sub-Antarctic volcano]. BBC News, 2 February 2016</ref> Volcanic activity has been regularly observed on Heard Island ever since its discovery by Europeans in 1853<ref>{{Cite journal |last=Fox |first=Jodi |date=27 April 2021 |title=Construction of an intraplate island volcano - Unravelling the volcanic history of Heard Island. - Supplementary material |url=https://doi.org/10.1007/s00445-021-01452-5 |journal=Bulletin of Volcanology |volume=37 |pages=1-86}}</ref> producing small lava flows almost annually between 2008 and 2020, so low-level volcanic activity (small vapour plumes, lava lake) is frequent or perhaps even continuous.<ref>{{Cite journal |last=Fox |first=Jodi |date=27 April 2021 |title=Construction of an intraplate island volcano: the volcanic history of Heard Island |url=https://link.springer.com/article/10.1007/s00445-021-01452-5 |journal=Bulletin of Volcanology |volume=83 |issue=37 |pages=1-21 |via=Springer}}</ref> Low-level volcanic activity is punctuated by more vigorous episodes of activity that are detectable via satellite and include large vapour plumes and lava flows{{snd}}satellite imagery suggests an ongoing eruption with lava effusion and mudflow as of 21 September 2025.{{Citation needed|date=September 2025}}

Heard Island and the McDonald Islands have no ports or harbours; ships must anchor offshore. The coastline is {{convert|101.9|km|mi|abbr=on}} in extent, and Australia claims a {{convert|12|nmi|mi km|0|abbr=on}} [[Exclusive economic zone|territorial sea]] and {{convert|200|nmi|mi km|0|abbr=on}} exclusive fishing zone around the islands.<ref name="CIA World Factbook" />

===Glacier retreat===
{{See also|Retreat of glaciers since 1850|Glacier mass balance}}
Heard Island is a heavily glaciated, [[subantarctic]] [[volcanic island]] located in the [[Southern Ocean]], roughly {{convert|4000|km|mi nmi|abbr=on}} southwest of Australia. Eighty percent of the island is covered in ice, with glaciers descending from {{convert|2400|m|ft|abbr=on}} to [[sea level]].<ref name="Allis1986">{{Cite journal
|author1=Ian F. Allison |author2=Peter L. Keage
|name-list-style=amp |title=Recent changes in the glaciers of Heard Island
|journal=Polar Record
|volume=23
|pages=255–272
|year=1986
|doi=10.1017/S0032247400007099
|issue=144|bibcode=1986PoRec..23..255A
|s2cid=130086301}}</ref> Due to the steep [[topography]] of Heard Island, most of its glaciers are relatively thin (averaging only about {{convert|55|m|ft|round=5|abbr=on}} in depth).<ref name="Ruddell">{{Cite web
|author=Andrew Ruddell
|date=25 May 2010
|url=http://www.aad.gov.au/default.asp?casid=2100
|title=Our subantarctic glaciers: why are they retreating?
|publisher=Glaciology Program, Antarctic CRC and AAD
|access-date=5 June 2010
|archive-url=https://web.archive.org/web/20091002074124/http://www.aad.gov.au/default.asp?casid=2100
|archive-date=2 October 2009
|url-status=dead}}</ref> The presence of glaciers on Heard Island provides an excellent opportunity to measure the rate of glacial retreat as an indicator of climate change.<ref name="aad2008">{{Cite web
|date=8 October 2008
|url=http://www.aad.gov.au/default.asp?casid=35356
|title='Big brother' monitors glacial retreat in the sub-Antarctic
|publisher=Australian Antarctic Division
|location=Kingston, Tasmania, Australia
|access-date=7 June 2010
|archive-url=https://web.archive.org/web/20090930211450/http://www.aad.gov.au/default.asp?casid=35356
|archive-date=30 September 2009
|url-status=dead}}</ref>

Available records show no apparent change in [[glacier mass balance]] between 1874 and 1929. Between 1949 and 1954, marked changes were observed to have occurred in the ice formations above {{convert|5000|ft|m|order=flip}} on the southwestern slopes of Big Ben, possibly as a result of volcanic activity. By 1963, major recession was obvious below {{convert|2000|ft|m|order=flip|sigfig=1}} on almost all glaciers, and minor recession was evident as high as {{convert|5000|ft|m|order=flip}}.<ref name="Budd1970">{{Cite journal
|author1=G.M. Budd |author2=P.J. Stephenson |title=Recent glacier retreat on Heard Island
|journal=International Association for Scientific Hydrology
|volume=86
|pages=449–458
|year=1970
|url=http://iahs.info/redbooks/a086/086046.pdf
|access-date=7 June 2010}}</ref>

The coastal ice cliffs of [[Brown Glacier|Brown]] and [[Stephenson Glacier|Stephenson]] Glaciers, which in 1954 were over {{convert|50|ft|m|order=flip}} high, had disappeared by 1963 when the glaciers terminated as much as {{convert|100|yard|m|order=flip|sigfig=1}} inland.<ref name="Budd1970" /> [[Baudissin Glacier]] on the north coast, and [[Vahsel Glacier]] on the west coast have lost at least {{convert|100|and|200|ft|m|order=flip|sigfig=1}} of ice vertically, respectively.<ref name="Budd1970" /> Winston Glacier, which retreated approximately {{convert|1|mi|order=flip}} between 1947 and 1963, appears to be a very sensitive indicator of glacier change on the island. The young [[moraine]]s flanking [[Winston Lagoon]] show that Winston Glacier has lost at least {{convert|300|ft|m|order=flip|sigfig=1}} of ice vertically within a recent time period.<ref name="Budd1970" /> [[Jacka Glacier]] on the east coast of [[Laurens Peninsula]] has also demonstrated marked recession since 1955.<ref name="Budd1970" />

Retreat of glacier fronts across Heard Island is evident when comparing [[Aerial photography|aerial photograph]]s taken in December 1947 with those taken on a return visit in early 1980.<ref name="Allis1986" /><ref name="Thost2008">{{Cite journal
|author1=Douglas E. Thost
|author2=Martin Truffer
|title=Glacier Recession on Heard Island, Southern Indian Ocean
|journal=Arctic, Antarctic, and Alpine Research
|volume=40
|issue=1
|pages=199–214
|date=February 2008
|doi=10.1657/1523-0430(06-084)[THOST]2.0.CO;2
|s2cid=130245283
|doi-access=free}}</ref> Retreat of Heard Island glaciers is most dramatic on the eastern section of the island, where the [[Glacier terminus|termini]] of former [[tidewater glacier]]s are now located inland.<ref name="Allis1986" /> Glaciers on the northern and western coasts have narrowed significantly, while the area of glaciers and [[ice cap]]s on Laurens Peninsula have shrunk by 30 to 65%.<ref name="Allis1986" /><ref name="Ruddell" />

Between 1947 and 1988, the total area of Heard Island's glaciers decreased by 11%, from {{convert|288|km2|sqmi}} (roughly 79% of the total area of Heard Island) to only {{convert|257|km2|sqmi}}.<ref name="Ruddell" /> A visit to the island in the spring of 2000 found that the Stephenson, Brown and Baudissin glaciers, among others, had retreated even further.<ref name="Ruddell" /><ref name="Thost2008" /> The terminus of Brown Glacier has retreated approximately {{convert|1.1|km|mi}} since 1950.<ref name="aad2008" /> The total ice-covered area of Brown Glacier is estimated to have decreased by roughly 29% between 1947 and 2004.<ref name="Thost2008" /> This degree of loss of glacier mass is consistent with the measured increase in temperature of {{convert|0.9|C-change}} over that time span.<ref name="Thost2008" />

Possible causes of glacier recession on Heard Island include:
# Volcanic activity
# Southward movement of the [[Antarctic Convergence]]: such a movement might cause glacier retreat through a rise in sea and air temperatures
# Climatic change

The [[Australian Antarctic Division]] conducted an expedition to Heard Island during the [[austral summer]] of 2003–2004. A small team of scientists spent two months on the island, conducting studies on [[Bird|avian]] and terrestrial biology and [[glaciology]]. Glaciologists conducted further research on the Brown Glacier in an effort to determine whether glacial retreat is rapid or punctuated. Using a portable [[Echo sounding|echo sounder]], the team took measurements of the volume of the glacier. Monitoring of climatic conditions continued, with an emphasis on the impact of [[Foehn wind]]s on glacier mass balance.<ref name="heard">{{Cite web
|url=http://www.heardisland.aq/history/research-expeditions/australian-research-expeditions
|title=Australian Research Expeditions
|publisher=[[Department of the Environment, Water, Heritage and the Arts]], [[Australian Antarctic Division]], Territories, Environment and Treaties Section
|location=Kingston, Tasmania, Australia
|access-date=7 June 2010
|archive-date=16 February 2011
|archive-url=https://web.archive.org/web/20110216173822/http://www.heardisland.aq/history/research-expeditions/australian-research-expeditions
|url-status=dead}}</ref> Based on the findings of that expedition, the rate of loss of glacier ice on Heard Island appears to be accelerating. Between 2000 and 2003, repeat [[Global Positioning System|GPS]] [[Surveying|surface surveys]] revealed that the rate of loss of ice in both the [[ablation zone]] and the [[accumulation zone]] of Brown Glacier was more than double the average rate measured from 1947 to 2003. The increase in the rate of ice loss suggests that the glaciers of Heard Island are reacting to ongoing climate change, rather than approaching [[dynamic equilibrium]].<ref name="Thost2008" /> The retreat of Heard Island's glaciers is expected to continue for the foreseeable future.<ref name="Allis1986" />

===Wetlands===
{{unreferenced section|date=April 2025}}
Heard Island has a number of small [[wetland]] sites scattered around its coastal perimeter, including areas of [[wetland]] vegetation, lagoons or lagoon complexes, rocky shores and sandy shores, including the [[Elephant Spit]]. Many of these wetland areas are separated by active glaciers. There are also several short glacier-fed streams and glacial pools. Some wetland areas have been recorded on McDonald Island but, due to substantial volcanic activity since the last landing was made in 1980, their present extent is unknown.

The HIMI wetland is listed on the [[Directory of Important Wetlands in Australia]] and, in a recent analysis of Australian Commonwealth-managed wetlands, was ranked highest for nomination under the [[Ramsar Convention|Convention on Wetlands of International Importance Especially as Waterfowl Habitat (Ramsar Convention)]] as an internationally important wetland.

Six wetland types have been identified from HIMI covering approximately {{convert|1860|ha|0|lk=on}}: coastal 'pool complex' ({{convert|237|ha}}); inland 'pool complex' ({{convert|105|ha}}); vegetated seeps mostly on recent glaciated areas ({{convert|18|ha}}); glacial lagoons (1103 ha); non-glacial lagoons ({{convert|97|ha}}); Elephant Spit ({{convert|300|ha|0}}) plus some coastal areas. On Heard Island, the majority of these types suites are found below {{convert|150|m|0}} [[Height above mean sea level|asl]]. The wetland vegetation occurs in the 'wet mixed herbfield' and 'coastal biotic vegetation' communities described above.

The wetlands provide important breeding and feeding habitat for a number of Antarctic and [[subantarctic]] wetland animals. These include the [[southern elephant seal]] and [[Macaroni penguin|macaroni]], [[Gentoo penguin|gentoo]], [[King penguin|king]] and [[eastern rockhopper penguin|eastern rockhopper]] penguins, considered to be wetland [[species]] under the Ramsar Convention. Non-wetland vegetated parts of the islands also support penguin and other seabird colonies.

===Climate===
[[File:Heard Island Karman vortex street.jpg|thumb|[[Vortex shedding]] as winds pass Heard Island resulted in this [[Kármán vortex street]] in the clouds.]]
The islands have an Antarctic climate, or [[tundra climate]] (''ET'') under the [[Köppen climate classification]], tempered by their maritime setting. The weather is marked by low seasonal and daily temperature ranges; persistent and generally low-lying cloud cover; frequent precipitation and strong winds. Snowfall occurs throughout the year. Monthly average temperatures at [[Atlas Cove]] (at the northwestern end of Heard Island) range from {{convert|0.0|to|4.2|°C|°F}}, with an average daily range of {{convert|3.7|to|5.2|°C|°F}} in summer and {{convert|-0.8|to|0.3|°C|°F}} in winter. The winds are predominantly westerly and persistently strong. At Atlas Cove, monthly average wind speeds range between around {{convert|26|and|33.5|km/h|mph|abbr=on}}. Gusts in excess of {{convert|180|km/h|mph|0|abbr=on}} have been recorded.

Annual precipitation at sea level on Heard Island is in the order of {{convert|1300|to|1900|mm|in|1|abbr=on}}; rain or snow falls on about three out of four days.<ref>HIMI official website.</ref> According to the Australian [[Bureau of Meteorology]], Heard Island receives an average of 96.8 snowy days annually at Atlas Cove.<ref>{{cite web | url=http://www.australianweathernews.com/snow/Snow%20days%20descending.htm |title=Snowy Days (96.8)}}</ref>

Meteorological records at Heard Island are incomplete.
{{Weather box
|location = Heard Island (1981–2010); 12 m AMSL; 53.10° S, 73.71° E
|metric first = yes
|single line = yes
|Jan record high C = 20.1
|Feb record high C = 18.0
|Mar record high C = 19.9
|Apr record high C = 20.4
|May record high C = 19.3
|Jun record high C = 14.0
|Jul record high C = 15.0
|Aug record high C = 15.4
|Sep record high C = 16.8
|Oct record high C = 16.4
|Nov record high C = 14.6
|Dec record high C = 19.2
|Jan high C = 6.4
|Feb high C = 6.5
|Mar high C = 6.3
|Apr high C = 5.3
|May high C = 3.7
|Jun high C = 2.3
|Jul high C = 2.2
|Aug high C = 2.2
|Sep high C = 2.2
|Oct high C = 3.3
|Nov high C = 4.1
|Dec high C = 5.4
|year high C =
|Jan mean C = 4.7
|Feb mean C = 4.8
|Mar mean C = 4.6
|Apr mean C = 3.6
|May mean C = 2.2
|Jun mean C = 0.9
|Jul mean C = 0.5
|Aug mean C = 0.4
|Sep mean C = 0.5
|Oct mean C = 1.5
|Nov mean C = 2.4
|Dec mean C = 3.8
|year mean C =
|Jan low C = 3.0
|Feb low C = 3.1
|Mar low C = 2.8
|Apr low C = 1.9
|May low C = 0.7
|Jun low C = -0.6
|Jul low C = -1.1
|Aug low C = -1.4
|Sep low C = -1.1
|Oct low C = -0.2
|Nov low C = 0.7
|Dec low C = 2.1
|year low C =
|Jan record low C = -0.5
|Feb record low C = 0.2
|Mar record low C = -1.7
|Apr record low C = -2.9
|May record low C = -4.8
|Jun record low C = -7.2
|Jul record low C = -6.2
|Aug record low C = -11.5
|Sep record low C = -8.6
|Oct record low C = -7.1
|Nov record low C = -6.2
|Dec record low C = -0.7
|precipitation colour=green
|Jan precipitation mm =
|Feb precipitation mm =
|Mar precipitation mm =
|Apr precipitation mm =
|May precipitation mm =
|Jun precipitation mm =
|Jul precipitation mm =
|Aug precipitation mm =
|Sep precipitation mm =
|Oct precipitation mm =
|Nov precipitation mm =
|Dec precipitation mm =
|year precipitation mm =
|unit precipitation days = 1 mm
|Jan precipitation days =
|Feb precipitation days =
|Mar precipitation days =
|Apr precipitation days =
|May precipitation days =
|Jun precipitation days =
|Jul precipitation days =
|Aug precipitation days =
|Sep precipitation days =
|Oct precipitation days =
|Nov precipitation days =
|Dec precipitation days =
|year precipitation days =
|source 1 =Météo climat stats<ref>{{cite web |url=http://meteo-climat-bzh.dyndns.org/listenormale-1981-2010-1-p97.php|title=Moyennes 1961–1990 Australie (Ile Heard)|language=fr|access-date=11 November 2019}}</ref>
|source 2= Météo Climat<ref>{{cite web|url=http://meteo-climat-bzh.dyndns.org/station-31.php|title=Météo Climat stats for Ile Heard |publisher=Météo Climat|access-date=11 November 2019}}</ref>
}}

===Biodiversity===
Most of the flora species are mosses and [[lichen]]s, with just twelve [[vascular plant]] species. The main indigenous animals are insects, along with large populations of ocean-going seabirds, penguins and seals.<ref>{{WWF ecoregion|name=Southern Indian Ocean Islands tundra|id=an1104}}</ref>

{{see also|List of non-avian biota of Heard Island and McDonald Islands}}

====Flora====
[[File:(The abode of science on Heard Island, BANZARE, 1929) (6173425701).jpg|thumb|right|200px|This 1929 photo of a scientific expedition shows some of Heard Island's mosses in the background.]]
There is vegetation, mostly mosses and lichens, on almost {{convert|20|km2}} of Heard Island's coastal, low-elevation areas.<ref name="plants">{{cite web |title=Plants of Heard Island and McDonald Islands |url=https://www.antarctica.gov.au/antarctic-operations/stations/other-locations/heard-island/nature/plants/ |website=[[Australian Antarctic Program]] |publisher=Government of Australia |access-date=3 April 2025}}</ref> There is not much plant diversity and there are very few [[flowering plant]] species and no trees or [[fern]]s.<ref name="plants" /> There are twelve vascular species on Heard Island, of which five are also on McDonald Island. The limited flora is due to the severe climate and limited ice-free areas.<ref name="plants" />

Vascular species:
{{Div col |colwidth=20em}}
*''[[Acaena magellanica]]''
*''[[Azorella]]''
*''[[Callitriche antarctica]]''
*''[[Colobanthus kerguelensis]]''
*''[[Deschampsia antarctica]]''
*''[[Leptinella plumosa]]''
*''[[Montia fontana]]''
*''[[Poa annua]]''
*''[[Poa cookii]]''
*''[[Poa kerguelensis]]''
*''[[Pringlea antiscorbutica]]''
*''[[Ranunculus crassipes]]''
*[[Bryophyte]]s (mosses and [[liverwort]]s)<ref name="plants" />
{{Div col end}}

Bryophytes, such as mosses and liverworts, can grow in places of the islands that other plants do not thrive in, such as on rock faces. [[Lichen]]s grow in many places on Heard Island with exposed rocks.<ref name="plants" /> Ninety species of lichens have been recorded from Heard Island and they are common on exposed rock, dominating the vegetation in some areas.<ref>{{cite journal |last1=Øvstedal |first1=D.O. |last2=Gremmen |first2=N.J.M. |title=Additions and corrections to the lichens of Heard Island |journal=The Lichenologist |volume=40 |issue=3 |year=2008 |doi=10.1017/S002428290800741X |pages=233–242}}</ref>

Heard Island does not have human-introduced plants, but the island does have one non-native plant: ''[[Poa annua]]'', a European grass. It may have come naturally from the [[Kerguelen Islands]], where it is widely present. The ''Poa annua'' grass may have been spread to the island by winds and by animals such as seabirds and seals.<ref name="plants" />

====Mammals====
{{further|List of mammals of Heard Island and McDonald Islands}}
[[File:Sea-Elephant Fishery 2 bis.jpg|thumb|Processing [[elephant seal]]s on Heard Island – a 19th-century scene.]]
[[Seal hunting|Sealing]] at Heard Island lasted from 1855 to 1910, during which time 67 sealing vessels are recorded visiting, nine of which were wrecked off the coast.{{sfn |Headland |2018 |p=167}} Relics that survive from that time include [[try pot]]s, [[cask]]s, hut ruins, graves, and inscriptions. Sealing caused the seal populations on Heard Island to either become locally extinct or reduced to levels too low to exploit economically. Modern sealers visited from [[Cape Town]], South Africa, in the 1920s.{{sfn |Headland |2018 |p=167}} Since then the seal populations generally have increased and are protected. Seals breeding on Heard include the [[southern elephant seal]], the [[Antarctic fur seal]], and the [[subantarctic fur seal]]. [[Leopard seal]]s visit regularly in winter to [[hauling-out|haul-out]] though they do not breed on the islands. [[Crabeater seal|Crabeater]], [[Ross seal|Ross]] and [[Weddell seal]]s are occasional visitors.<ref>{{cite web |url=http://www.heardisland.aq/nature/animals-of-himi/seals |title=Seals |access-date=23 February 2011 |website=Heard Island and McDonald Islands: Seals |publisher=Department of Sustainability, Environment, Water, Population and Communities, Australia}}</ref>

====Birds====
{{Further|List of birds of Heard and McDonald Islands}}
Heard Island and the McDonald Islands are free from introduced predators and provide crucial breeding habitat in the middle of the vast Southern Ocean for a range of birds. The surrounding waters are important feeding areas for birds and some scavenging species also derive sustenance from their cohabitants on the islands. The islands have been identified by [[BirdLife International]] as an [[Important Bird Area]] because they support very large numbers of nesting seabirds.<ref>{{cite web |website=BirdLife International |date=2011 |title=Important Bird Areas factsheet: Heard and McDonald Islands |url=http://www.birdlife.org/ |access-date=23 December 2011}}</ref>

Nineteen species of birds have been recorded as breeding on Heard Island<ref>Woehler, E.J. & Croxall, J.P. 1991. 'Status and conservation of the seabirds of Heard Island and the McDonald Islands', in Seabird – status and conservation: a supplement, ICBP Technical Publication 11. International Council for Bird Preservation, Cambridge. pp 263–277.</ref> and the McDonald Islands, although recent volcanic activity at the McDonald Islands in the last decade{{when|date=April 2025}} is likely to have reduced vegetated and un-vegetated nesting areas.<ref name="Woehler, E.J. 2006">Woehler, E.J. (2006). 'Status and trends of the seabirds of Heard Island, 2000', in Heard Island: Southern Ocean Sentinel. ed. Green, K. & Woehler, E. Surrey Beattie.</ref>

Penguins are by far the most abundant birds on the islands, with four breeding species present, comprising [[King penguin|king]], [[Gentoo penguin|gentoo]], [[Macaroni penguin|macaroni]], and [[eastern rockhopper penguin]]s. The penguins mostly colonise the coastal [[Tussock grass|tussock]] and [[grassland]]s of Heard Island, and have previously been recorded as occupying the flats and gullies on McDonald Island.

Other seabirds recorded as breeding at Heard Island include three species of [[albatross]] ([[Wandering albatross|wandering]], [[Black-browed albatross|black-browed]], and [[light-mantled albatross]]es), [[southern giant petrel]]s, [[Cape petrel]]s, four species of burrowing [[petrel]]s ([[Antarctic prion|Antarctic]] and [[Fulmar prion]]s, [[Common diving-petrel|common]] and [[South Georgia diving petrel]]s), [[Wilson's storm petrel]]s, [[kelp gull]]s, [[subantarctic skua]]s, [[Antarctic tern]]s, and the [[Heard shag]].<ref name="Woehler, E.J. 2006" /> Although not a true seabird, the Heard Island subspecies of the [[black-faced sheathbill]] also breeds on the island. Both the [[Cormorant|shag]] and the [[sheathbill]] are endemic to Heard Island.

A further 28 seabird species are recorded as either non-breeding visitors or have been noted during 'at-sea surveys' of the islands. All recorded breeding species, other than the Heard Island sheathbill, are listed marine species under the Australian Environmental Protection and Biodiversity Act (1999, four are listed as threatened species and five are listed as migratory species. Under the EPBC Act a recovery plan has been made for albatrosses and giant petrels, which calls for ongoing population monitoring of the species found at HIMI, and at the time of preparing this plan a draft recovery plan has also been made for the [[Heard Island shag|Heard Island cormorant (or shag)]] and Antarctic tern.

The recorded populations of some seabird species found in the Reserve have shown marked change. The king penguin population is the best-studied seabird species on Heard Island and has shown a dramatic increase since first recorded in 1947–1948, with the population doubling every five years or so for more than 50 years.{{when|date=April 2025}}

A paper reviewing population data for the black-browed albatross between 1947 and 2000–2001 suggested that the breeding population had increased to about three times that present in the late 1940s,<ref>{{cite journal |last1=Woehler |first1=E. J. |last2=Auman |first2=H. J. |last3=Riddle |first3=M. J. |year=2002 |title=Long-term population increase of black-browed albatrosses ''Thalassarche melanophrys'' at Heard Island, 1947/1948–2000/2001 |journal=Polar Biology |volume=25 |issue=12 |pages=921–927 |doi=10.1007/s00300-002-0436-1 |bibcode=2002PoBio..25..921W |s2cid=2425658}}</ref> although a Convention for the Conservation of Antarctic Marine Living Resources CCAMLR) Working Group was cautious about the interpretation of the increasing trend given the disparate nature of the data,<ref>SC–CAMLR 2002. Report of the Working Group on Fish Stock Assessment. Report of the Twenty-First Meeting of the Scientific Committee for the Conservation of Antarctic Marine Living Resources, Hobart, Australia.</ref> as discussed in the paper. The discovery of a large, previously unknown, colony of Heard shags in 2000–2001 at Cape Pillar raised the known breeding population from 200 pairs to over 1000 pairs.<ref name="Woehler, E.J. 2006" /> The breeding population of southern giant petrels decreased by more than 50% between the early 1950s and the late 1980s.

====Invertebrates====
{{unreferenced section|date=January 2012}}
Heard Island supports a relatively low number of terrestrial [[invertebrate]] species compared to other Southern Ocean islands, in parallel with the low species richness in the flora–that is, the island's isolation and limited ice-free area. [[Endemism]] is also generally low and the invertebrate fauna is exceptionally pristine with few, if any, (successful) human-induced introductions of alien species. Two species, including the [[thrips]] ''[[Apterothrips apteris]]'' and the [[mite]] ''[[Tyrophagus putrescentiae]]'' are thought to be recent, possibly natural, introductions. An exotic species of earthworm, ''[[Dendrodrilus rubidus]]'', was also collected in 1929 from a dump near Atlas Cove, and has recently been collected from a variety of [[habitat]]s including wallows, streams and lakes on Heard Island.

The [[arthropod]]s of Heard Island are comparatively well known, with 54 species of mite and tick, one spider, and eight [[springtail]]s recorded. A study over the summer of 1987–1988 at Atlas Cove showed overall densities of up to 60,000 individual springtails per square metre (10.75 sq ft) in soil under stands of ''[[Pringlea antiscorbutica]]''. Despite a few recent{{when|date=April 2025}} surveys, the non-arthropod invertebrate fauna of Heard Island remain poorly known.

Beetles and flies dominate Heard Island's known insect fauna, which comprises up to 21 species of [[ectoparasite]] (associated with birds and seals) and up to 13 free-living species. Approximately half of the free-living insects are habitat-specific, while the remainder are generalists found in a variety of habitats, being associated with either [[Supralittoral zone|supralittoral]] or [[intertidal zone]]s, ''[[Poa cookii]]'' and ''[[Pringlea antiscorbutica]]'' stands, bryophytes, lichen-covered rocks, exposed rock faces, or the underside of rocks. There is a pronounced seasonality to the insect fauna, with densities in winter months dropping to a small percentage (around 0.75%) of the summer maximum. Distinct differences in relative abundances of species between habitats has also been shown, including a negative relationship between altitude and body size for Heard Island [[weevil]]s ([[genus]] ''[[Ectemnorhinus]]'').

The fauna of the freshwater pools, lakes, streams and mires found in the coastal areas of Heard Island are broadly similar to those on other subantarctic islands of the southern Indian Ocean. Many species reported from Heard Island are found elsewhere. Some sampling of freshwater fauna has been undertaken during recent expeditions and records to date{{when|date=April 2025}} indicate that the freshwater fauna includes a species of [[Protista]], a [[gastrotrich]], two species of [[tardigrade]], at least four species of [[nematode]], 26 species of [[rotifer]], six species of [[annelid]], and 14 species of arthropod.

As with the other shore biota, the marine macro-invertebrate fauna of Heard Island is similar in composition and local distribution to other subantarctic islands, although relatively little is known about the Heard Island communities compared with the well-studied fauna of some other islands in the subantarctic region, such as [[Macquarie Island|Macquarie]] and Kerguelen.

Despite Heard Island's isolation, species richness is considered to be moderate, rather than depauperate, although the number of endemic species reported is low. The large macro-[[alga]] ''[[Durvillaea antarctica]]'' supports a diverse array of invertebrate [[Taxon|taxa]] and may play an important role in transporting some of this fauna to Heard Island.

The rocky shores of Heard Island exhibit a clear demarcation between fauna of the lower [[kelp]] [[Holdfast (biology)|holdfast]] zone and the upper shore zone community, probably due to effects of desiccation, predation, and freezing in the higher areas. The [[limpet]] ''[[Nacella kerguelensis]]'' is abundant in the lower part of the shore, being found on rock surfaces and on kelp holdfasts. Other common but less abundant species in this habitat include the [[chiton]] ''[[Hemiarthrum setulosum]]'' and the [[starfish]] ''[[Anasterias mawsoni]]''. The [[amphipod]] ''[[Hyale (amphipod)|Hyale]]'' sp. and the [[isopod]] ''[[Cassidinopsis]]'' sp. are closely associated with the kelp. Above the kelp holdfast zone, the [[Littorinidae|littorinid]] ''[[Laevilitorina heardensis|Laevilitorina (Corneolitorina) heardensis]]'' and the [[bivalve]] [[mollusk]] ''[[Kidderia bicolor]]'' are found in well-sheltered situations, and another bivalve, ''[[Gaimardia trapesina trapesina]]'', has been recorded from immediately above the holdfast zone. [[Oligochaetes]] are also abundant in areas supporting porous and spongy layers of [[algal mat]].

==See also==
*[[List of Antarctic and subantarctic islands|List of Antarctic and sub-Antarctic islands]]
*[[List of glaciers in the Antarctic]]
*[[List of islands of Australia]]
*[[Needle Island]]
*[[Sunken Rock]]
*[[Wakefield Reef]]
*[[2025 in Antarctica]]

==References==
{{Reflist |30em}}

==Sources==
{{Refbegin |30em |indent=yes}}
*{{cite journal|first=Max|last=Downes|year=2002|url=https://www.antarctica.gov.au/site/assets/files/64914/arn_104.pdf|title=First visitors to Heard Island|publisher=Australian Antarctic Division|journal=ANARE Research Notes|issue=104}}
*{{cite book |editor-last=Headland |editor-first=R.K. |year=2018 |title=Historical Antarctic Sealing Industry |publisher=Scott Polar Research Institute, University of Cambridge |isbn=978-0-901021-26-7}}
*{{cite journal|url=https://eprints.utas.edu.au/13601/4/2000_McGowan_On_rst.pdf|title=On their own: towards an analysis of sealers' sites on Heard Island|first=Angela|last=McGowan|year=2000|volume=133|number=2|journal=Papers and Proceedings of the Royal Society of Tasmania|pages=61–69}}
{{Refend}}

==Further reading==
{{Refbegin |30em |indent=yes}}
*Commonwealth of Australia (2014). ''Heard Island and McDonald Islands Marine Reserve Management Plan 2014–2024'', Department of the Environment, Canberra. {{ISBN|978-1876934-255}}. Available at [http://heardisland.antarctica.gov.au/ Heard Island and McDonald Islands – Australian Antarctic Program]
*Australian Government. (2005) ''Heard Island and McDonald Islands Marine Reserve Management Plan''. Australian Antarctic Division: Kingston (Tas). {{ISBN|1-876934-08-5}}.
*Green, Ken and Woehler Eric (eds). (2006) ''Heard Island: Southern Ocean Sentinel''. Chipping Norton: Surrey Beatty and Sons. {{ISBN|9780949324986}}.
*Scholes, Arthur. (1949) ''Fourteen men; story of the Australian Antarctic Expedition to Heard Island''. Melbourne: F.W. Cheshire.
*Smith, Jeremy. (1986) ''Specks in the Southern Ocean''. Armidale: University of New England Press. {{ISBN|0-85834-615-X}}.
*LeMasurier, W. E. and Thomson, J. W. (eds.). (1990) ''Volcanoes of the Antarctic Plate and Southern Oceans''. [[American Geophysical Union]]. {{ISBN|0-87590-172-7}}.
*{{cite journal |author1=Patrick G. Quilty |author2=Graeme Wheller |title=Heard Island and the McDonald Islands: A Window into the Kerguelen Plateau |journal=Papers and Proceedings of the Royal Society of Tasmania |volume=133 |issue=2 |pages=1–12 |year=2000 |url=https://figshare.utas.edu.au/articles/journal_contribution/Heard_Island_and_the_McDonald_Islands_a_window_into_the_Kerguelen_Plateau/24484135/1?file=43016845}}
*{{cite journal |author1=Brian Roberts |title=Historical Notes on Heard and McDonald Islands |journal=Polar Record |volume=5 |issue=40 |pages=580–584 |year=1950 |url=https://www.cambridge.org/core/journals/polar-record/article/abs/historical-notes-on-heard-and-mcdonald-islands/FCFE9FBF72E6831A118820E6EEAFF153 |doi=10.1017/s0032247400045204|bibcode=1950PoRec...5..580R |url-access=subscription}}
{{Refend}}

==External links==
*{{Official website|https://www.antarctica.gov.au/antarctic-operations/stations/other-locations/heard-island/|Heard Island and McDonald Islands, Australian Antarctic Program}}
*[https://www.antarctica.gov.au/antarctic-operations/stations/other-locations/heard-island/location-geography/mapping/ Heard Island and McDonald Islands mapping], Australian Antarctic Program
*[https://www.awe.gov.au/parks-heritage/heritage/places/world/heard-mcdonald World heritage listing for Heard Island and McDonald Islands]
*{{Cite CIA World Factbook|country=Heard Island and McDonald Islands}}
*{{wikiatlas|Heard Island and McDonald Islands}}
*{{Webarchive|url=https://web.archive.org/web/20170215235420/http://heardisland.antarctica.gov.au/gallery |date=15 February 2017 |title=Image gallery, Australian Antarctic Division}}
*[https://whc.unesco.org/pg.cfm?cid=31&id_site=577 UNESCO World Heritage site entry]
*{{webarchive |url=https://web.archive.org/web/20060317165141/http://www.btinternet.com/~sa_sa/heard_island/heard.html |date=17 March 2006 |title=Heard Island, The South Atlantic & Subantarctic Islands}}
*[http://www.heardisland.org/ Heard Island: The Cordell Expedition 2016] {{Webarchive|url=https://web.archive.org/web/20160205214740/http://www.heardisland.org/ |date=5 February 2016}}

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