Waldegrave Islands

Waldegrave Islands is an island group in the Australian state of South Australia located in the Investigator Group about 2.5 km northwest by west of Cape Finniss on the west coast of Eyre Peninsula. The group consists of Waldegrave Island, Little Waldegrave Island and according to some sources, a pair of rocks known as the Watchers. The group is notable as a breeding site for Australian sea lions and Cape Barren geese. The group has enjoyed protected area status since the 1960s and as of 1972 has been part of the Waldegrave Islands Conservation Park.

Description
Waldegrave Islands is an island group located about 2.5 km northwest by west of Cape Finniss and about 8.5 km northwest by west of the town of Elliston on the west coast of Eyre Peninsula in South Australia.

The group consist of the following islands: Waldegrave Island (also called East Waldegrave Island and East Island in some sources), Little Waldegrave Island (also called West Waldegrave Island, West Island and Seal Island in some sources) and according to some sources, a pair of rocks known as the Watchers.

Both islands can be accessed via the rocky coast on their northern sides which is sheltered from southerly swells.

Waldegrave Island
Waldegrave Island is a flat topped island with steep sides having a length of about 3.5 km (in the east-west direction), a maximum height in the range of 37 - 39 m and an area of 292 ha. Its east coast which is about 1.5 km long is terminated at the north east with a point named McLachlan Point and the south by a point named Point Watson. It overlaps the seaward boundary of Anxious Bay as proclaimed by the Australian government in 1987 and again in 2006 under the Seas and Submerged Lands Act 1973.

Little Waldegrave Island
Little Waldegrave Island is located about 1 km west of Waldegrave Island. It is a flat topped island with steep sides having a length of about 1 km (in the east-west direction), a maximum height in the range of 25 m and an area of 32 ha.

The Watchers
The Watchers are a pair of rocks that are spaced about 1 nmi apart and which are located about 1.7 nmi west of Little Waldegrave Island. The western rock has a charted height of 7 m and is reported in another source as being 7.3 m. The eastern rock is charted  chart as an intertidal reef.

Formation, geology and oceanography
The Waldegrave Islands were formed about 6000 years ago following the rise of sea levels at the start of the Holocene. The Waldegrave Islands consists of a ‘crystalline basement (covered by calcareous aeolianite of varying thickness)’ which outcrops to a height of 5 m on Little Waldegrave Island and which exists as a submerged reef connecting both islands. The Waldegrave Islands are considered to be ‘remnants of a once more prominent Cape Finnis(s)’ with the ‘remains of the bridging isthmus lie as a submerged reef connecting Cape Finnis(s)’ to Waldegrave Island at its north-eastern tip.

The Watchers are reported geologically as being ‘two isolated outcrops of crystalline rocks’.

Waters around Waldegrave and Little Waldegrave Islands drop to depths of 15 - 20 m within about 300 - 1000 m of its north, west and south coasts. Its east coast drops into water of depths between 5 - 10 m due to the presence of the submerged reef structure between it and Cape Finniss.

The Watchers are associated with a submerged reef system independent of that underlying the Waldegrave and Little Waldegrave Islands. Waters adjoining the Watchers drop to depths of 15 m within about 300 m immediately south and west of the western rock and about 600 m to its north east.

Flora
A survey carried out during 1979 on Waldegrave Island found 26 species of plant that occurred in the following ‘five distinctive groupings’: introduced pasture, ‘heavy infestations of African Boxthorn and native shrublands of native juniper and coast daisy-bush and saltbush. A survey carried out in 1980 on Little Waldegrave Island found southern seaheath, sea celery and nine other species of plant including ‘colonising weeds such as African boxthorn and common iceplant’.

Fauna
A Survey carried out during 1979 on Waldegrave Island found the following species of birds: short-tailed shearwater, Cape Barren geese, masked plover, galah, white-fronted chat, little grassbird, Nankeen kestrel, black-faced shag, sooty oystercatcher, white-bellied sea eagle, various gulls and terns, and barn owl which prey on the population of bush rat. A survey carried out in 1980 on Little Waldegrave Island found a population of Australian sea lions and five species of birds including rock parrot, Cape Barren geese and little penguin. Surveys carried out on Little Waldegrave Island between February 2001 and May 2006 confirm the presence of the following bird species: white-faced heron, eastern reef egret, white-bellied sea eagle, swamp harrier, peregrine falcon, Nankeen kestrel, common greenshank, ruddy turnstone, red-necked stint, masked lapwing, rock parrot, sacred kingfisher, white-fronted chat, Australian raven, Richard's pipit, welcome swallow, silvereye and common starling.

Australian sea lion
Little Waldegrave Island is the site of a breeding colony of Australian sea lion. As of 1999, the population was reported as being 38. On the larger island, Flinders' expedition killed "a few" Australian sea lions.

Cape Barren geese
As of 1996, the Waldegrave Islands were considered to be the ’second most important breeding area’ for Cape Barren geese in South Australia and as having a breeding population of 20 pairs. As of 1999, the geese were reported as having a population of 350 and as staying ‘in the Elliston area for the summer, feeding in swamps around the margins of Lake Newland and on grain in wheat paddocks’.

Little penguin
The Waldegrave Islands have been reported as the site of a little penguin breeding colony. As of 1999, 300 pairs were reported in 1996 as being present on Waldegrave Island. As of 2006, the populations on Waldegrave and Little Waldegrave Islands were estimated as being respectively 600 in 2006 and as being ‘common’ in 1979.

European discovery and use
Matthew Flinders named the island group after William Waldegrave, 1st Baron Radstock on Wednesday, 10 February 1802.

The Waldegrave Islands is one of the island sites from which guano was mined under licence from the South Australian Government prior to 1919.

Prior to 1967, Waldegrave Island was used for grazing.

Protected areas status
The Waldegrave Islands first received protected area status as a fauna conservation reserve declared on 16 March 1967. The Waldegrave Islands along with the Watchers were proclaimed as a conservation park under the National Parks and Wildlife Act 1972 in 1972.