Current view: Text account
Site description (2008 baseline):
Site location and context
The Investigator Group is an archipelago comprised of three island groups off the western coast of the Eyre Peninsula. The northernmost of the three island groups lies 3 km offshore near Elliston. This group, which consists of Waldegrave (292 ha) and Little Waldegrave (32 ha) Islands, has calcanerite soils. The vegetation is mostly comprised of regenerating pasture (sheep were grazed on the island until 1967), with some areas of native shrubland dominated by Native Juniper and Coast Daisy-bush. The second of the three island groups lies 28 km offshore. This group consists of Flinders Island, which at 3642 ha is the largest island in the Investigator Group, and nearby Ward and Topgallant Islands. Flinders Island is leasehold land used for grazing. It has calcanerite and sandy soils and is mostly covered by pasture grasses, with some tourist accommodation and some small areas of heathland and Melaleuca woodland. Topgallant Island is a small island with very steep cliffs and some stunted shrubland. The vegetation of Ward Island consists of shrubland and heathland. The southernmost of the three island groups consists of Pearson Island (213 ha), the Veteran Isles (14 ha) and Dorothee Island (56 ha). Pearson Island is covered with shrubland and heathland and some interspersed patches of Casuarina and Melaleuca woodland. The Veteran Isles support low shrubland dominated by Marsh Saltbush and Twiggy Daisy-bush (Robinson et al. 1996). All islands of the IBA, with the exception of Flinders Island (leasehold) and Pearson Island (Lighthouse Reserve), are included in Waldegrave Islands Conservation Park or Investigator Group Conservation Park.
Large numbers of Short-tailed Shearwater (approximately 92,906 pairs in 1980) and White-faced Storm-Petrel (approximately 9426 pairs in 1980) breed within the IBA (Copley 1996). The Little Penguin also breeds within the IBA on Waldegrave (more than 300 pairs in one small area in 1991), Little Waldegrave (common in 1979; 2001-2006), Pearson (many burrows in 1976) and Dorothee (many burrows on northern half of island in 1976) Islands (Parker & Cox 1978; Copley 1996; Shaughnessy et al. 2008a). The biome-restricted Rock Parrot has been observed on most islands in the group. It was the second most common species of bird recorded on Pearson Island by Hornsby (1978) but numbers may be smaller than the reporting rate indicates. More than 50 Rock Parrots were recorded on each visit to Little Waldegrave in 2001-2006, with a maximum of 200 breeding in 2002 (Shaughnessy et al. 2008b).
Non-bird biodiversity: The IBA supports large numbers of Australian Sea-lions, smaller numbers of New Zealand Fur-seals, and the founding colony of the Pearson Island subspecies of the Black-footed Rock-wallaby.
Pressure/threats to key biodiversity
Monitor all islands for invasive species such as rats, and eradicate where possible. Investigate the impact of human disturbance, including fishing and farming, on key species.
THe IBA overlaps the Investigator Group Conservation Park and the Waldegrave Islands Conservation Park and contains the site of the Heritage Agreement 1003.
Flinders Island is leasehold. Other islands are owned and managed by the South Australian government.
Jason van Weenan and Christine Arnold (Department for Environment and Heritage) helped supply reports and data.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Investigator Islands (Australia). Downloaded from
https://datazone.birdlife.org/site/factsheet/investigator-islands-iba-australia on 22/11/2024.
