Investigator Group

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Investigator Group
Investigator Group is located in South Australia
Investigator Group
Location Great Australian Bight
The islands are an important area for Cape Barren geese

The Investigator Group is an archipelago comprising Flinders Island and five island groups off the western coast of the Eyre Peninsula, South Australia. It is named after HMS Investigator, which was captained by Matthew Flinders when he explored the area in 1802. It lies at the eastern end of the Great Australian Bight in the Southern Ocean. All the islands except Flinders Island, and a part of Pearson Island, are within the Investigator Group Wilderness Protection Area and the Waldegrave Islands Conservation Park.[1][2]



The Investigator Group is a group of islands and associated landforms that are located within an area extending for a distance of about 70 kilometres (38 nmi) south west from Cape Finniss on the west coast of Eyre Peninsula in South Australia. The group consists of the following islands and island groups placed in order of increasing distance from Cape Finniss: the Waldegrave Islands, The Watchers, Flinders Island, Topgallant Islands, the Ward Islands and the Pearson Isles.[3]

Waldgrave Islands[edit]

Further information: Waldegrave Islands

The northernmost group lies 3 km offshore near the small town of Elliston. It consists of Waldegrave (292 ha) and Little Waldegrave (32 ha) Islands. They have calcarenite soils and were grazed by sheep until 1967. The vegetation is mainly regenerating pasture, with patches of native shrubland dominated by Native Juniper and Coast Daisy-bush.[4]

The Watchers[edit]

Further information: The Watchers

The Watchers are a pair of rocks that are spaced about 1.9 kilometres (1 nmi) apart and which are located about 3.1 kilometres (1.7 nmi) west of Little Waldegrave Island. The western rock has a charted height of 7 metres (23 ft) and is reported in another source as being 7.3 metres (24 ft). The eastern rock is charted as an intertidal reef.[5][6][7][8][9]

Flinders Island[edit]

Flinders Island, which is 28 km offshore and at 36 km2 is the largest island in the Investigator Group. Flinders Island is leasehold land used for grazing. It has sandy, calcarenite soils, is mainly vegetated with pasture grasses, and has some remnant patches of heathland and Melaleuca woodland.[4]

Topgallant Islands[edit]

Further information: Topgallant Islands

Topgallant Islands are located 6 km to the east of Flinders Islands and is a small island with steep cliffs and some stunted shrubland.[4]

Ward Islands[edit]

Further information: Ward Islands

Ward Islands are located 16 km to the west of Flinders Island and is covered with shrubland and heathland.[4]

Pearson Islands[edit]

The southernmost group consists of Pearson Island (213 ha), the Veteran Isles (14 ha) and Dorothee Island (56 ha). Pearson Island, the second largest of the whole Investigator Group, and containing its highest point at 231 m above sea level, is vegetated with shrub and heathland with patches of Casuarina and Melaleuca woodland. The Veteran Isles support low shrubland dominated by Twiggy Daisy-bush and Marsh Saltbush. Lying 3 km south-south-west of the Veteran Isles is Dorothee Island, the most southerly of the Investigator Group.[4][10]



Little penguins[edit]

Little penguins breed on Waldegrave, Little Waldegrave, Pearson and Dorothee Islands. Little penguins were mentioned as being present on Pearson Island by a scientific expedition in 1923. They were found to be cohabiting the island with Australian sea lions. At this time the island had been cleared of New Zealand fur seals by sealers, who were still engaged in the 'massacre' of Australian sealions for their (albeit less lucrative) furs.[11]

In 2006, the little penguin colony on Pearson Island was 12,000 birds, making it the largest single colony in South Australia. As of 2011, the Pearson Island colony's status is unknown.[12] In 2013, Kangaroo Island tour operator visited Pearson Island and stated that the penguins there had disappeared.[13] A little penguin survey was scheduled to be conducted on Pearson Island by SARDI researchers in 2013.[14] As of March 2014, the SARDI survey's results remain unpublished.


European discovery and use[edit]

On Saturday, 13 February 1802, Flinders gave the name Investigator Group to the group of islands consisting of Flinders Island, the Pearson Islands, the Topgallant Islands, the Waldegrave Islands and Ward Islands.[15]

Protected area status[edit]

Reserves declared by the South Australian government[edit]

Protected area status has been conferred to all islands within the group with exception of the majority of Flinders Island and part of Pearson Island.[16][17] The Investigator Group Wilderness Protection Area comprises Ward Islands, Top Gallant Isles, Pearson Isles with exception of a portion of land on Pearson Island which is held by the Australian Maritime Safety Authority for "lighthouse purposes".[16] The Waldegrave Islands Conservation Park occupies the Waldegrave Island, Little Waldegrave Island and the Watchers. [17] A heritage agreement has been in force on Flinders Island since 1995 in respect to a strip of land along the north coast of the island extending west from the island’s most northerly headland, Point Malcolm.[18][4] As of 2012, the Investigator Marine Park includes the waters adjoining the following: Flinders Island, Topgallant Isles, the Ward Islands and the Pearson Isles.[19]

Non-statutory arrangements[edit]

The group has been identified by BirdLife International as an Important Bird Area (IBA) known as the Investigator Islands (sic) Important Bird Area because it is considered to support over 1% of the world population of Cape Barren geese and a population of the vulnerable fairy tern. The IBA probably also supports over 1% of the world populations of black-faced cormorants and Pacific gulls. Other birds for which the IBA is significant include large numbers of breeding short-tailed shearwaters and white-faced storm-petrels. The biome-restricted rock parrot has been recorded from most islands in the group.[4]

Citations and references[edit]


  1. ^ WAC, 2013, page 16-17
  2. ^ DoE, 2012
  3. ^ NGA, 2012, page 166
  4. ^ a b c d e f g BLI, 2015
  5. ^ RAN, 1979
  6. ^ DMH, 1985, chart 38
  7. ^ Robinson et al., 1996, page 188
  8. ^ "The Watchers". Gazetteer of Australia online. Geoscience Australia, Australian Government. 
  9. ^ NGA, 2012, page 165
  10. ^ Geoscience Australia, 1983. Topgallant 5730 1:100,000 topographic map, Edition 1.
  11. ^ "Lonely island. Scientists in the bight.". West Coast Sentinel. 1923-01-20. Retrieved 2015-02-08. 
  12. ^ Wiebken, A. Conservation Priorities for Little Penguin Populations in Gulf St Vincent SARDI, South Australia (2011-06). Retrieved 2014-01-26.
  13. ^ Winter, Caroline "Little Penguin decline hits SA tourism" AM, ABC, Australia (2013-07-27). Retrieved 2014-03-25.
  14. ^ Delaney, Jarrad "Search for penguins" West Coast Sentinel, Ceduna, South Australia (2013-07-24). Retrieved 2014-03-25.
  15. ^ Flinders, 1814 (1966), page 223
  16. ^ a b WAC, 2013, pages 16-17
  17. ^ a b DEH, 2006, page 5
  18. ^ DEH, 2006, page 12
  19. ^ DEWNR, 2012, pages 23 & 26


Coordinates: 33°45′S 134°30′E / 33.750°S 134.500°E / -33.750; 134.500