|Location||Great Australian Bight|
The Investigator Group is an archipelago comprising three scattered 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.
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.
The second group lies 28 km offshore. It consists of Flinders Island, which at 36 km2 is the largest island in the Investigator Group, with Ward Island and Topgallant Island. 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. Ward Island, 16 km to the west of Flinders, is covered with shrubland and heathland. Topgallant Island, 6 km to the east of Flinders, is a small island with steep cliffs and some stunted shrubland.
The third and 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.
The islands have been identified by BirdLife International as an Important Bird Area (IBA) because they 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.
Little Penguins breed on Waldegrave, Little Waldegrave, Pearson and Dorothee Islands. In 2006, the Little penguin colony on Pearson Island was 12,000 birds, making it the largest single colony in South Australia. The second largest colony is on Wardang Island in Spencer Gulf. As of 2011, the Pearson Island colony's status is unknown. In 2013, Kangaroo Island tour operator visited Pearson Island and stated that the penguins there had disappeared. A Little penguin survey was scheduled to be conducted on Pearson Island by SARDI researchers in 2013. As of March 2014, the SARDI survey's results remain unpublished.
- "Wilderness Advisory Committee Annual Report 2012-13". September 2013. pp. 16–17. ISSN 1832-9357. Retrieved 17 March 2014.
- "CAPAD 2012 South Australia Summary (see 'DETAIL' tab)". CAPAD 2012. Australian Government - Department of the Environment. 6 February 2014. Retrieved 6 February 2014.
- "Sites - Important Bird Areas (IBAs): Investigator Islands". Bird Life International. Retrieved 7 January 2014.
- Geoscience Australia, 1983. Topgallant 5730 1:100,000 topographic map, Edition 1.
- "IBA: Investigator Islands". Birdata. Birds Australia. c. 2007. Retrieved 7 January 2014. "at IBA search page, use term 'Investigator Islands'"
- Wiebken, A. Conservation Priorities for Little Penguin Populations in Gulf St Vincent SARDI, South Australia (2011-06). Retrieved 2014-01-26.
- Winter, Caroline "Little Penguin decline hits SA tourism" AM, ABC, Australia (2013-07-27). Retrieved 2014-03-25.
- Delaney, Jarrad "Search for penguins" West Coast Sentinel, Ceduna, South Australia (2013-07-24). Retrieved 2014-03-25.