Hunter Island Group

Site description (2008 baseline):

Site location and context
The Hunter Island IBA consists of numerous, varied islands off north-west Tasmania. It abuts the Robbins Passage and Boullanger Bay IBA to the south, which includes the seabird islands of Petrel Islands and Walker Island. Three Hummock Island (6967 ha) has a coastline of exposed granite outcrops interspersed with 10km of sandy beaches and dune areas. Eastern hills border a broad, flat plain in the centre of the island, and it gets its name from the highest three (100m, 160m and 237m). A series of swamps and lagoons have resulted from extensive dune systems blocking drainage from the plain, and thick vegetation with trees as high as 35m is mixed with abandoned pastoral land. Habitat types at Hunter Island (7330 ha) comprise a mix of cattle-grazed paddocks, swamps, heathland, thick scrub and woodland copses, and infrastructure on these larger islands includes settlements, lighthouses and airstrips. The whole of Hunter is taken as an IBA, partly because of its importance for Orange-bellied Parrot. Steep Island (22 ha) west of Hunter is a steep grassy island with very large numbers of shearwaters and penguins. Bird Island (44 ha) south-west of Hunter is rocky and scrubby but has large numbers of penguins and Sooty Oystercatchers. Stack Island (24 ha) is scrubby with Pacific Gull nesting around the edge. Penguin Islet (3 ha) has the largest diversity of breeding seabirds in Tasmania. The somewhat peripheral Trefoil Island (115 ha) is included here, though it could equally well be an IBA in its own right. Trefoil Island is steep and grassy with 698,262 pairs of Short-tailed Shearwater and 40 pairs of Pacific Gull. Little Trefoil (0.6 ha) has 15 pairs Pacific Gull. The spectacular Doughboys (12 ha) have sloping supratidal platforms, vertical cliffs and steeply sloping grassy hills. Other important islets to the south, extending to the far north-west of the Tasmanian mainland, include Henderson, Harbour and Murkay Islets, with 46 pairs of Pacific Gull.

Key biodiversity
Counts of the following species suggest that the whole IBA may support more than 1% of the world population. Common Diving-Petrel (IBA threshold is 70,000 pairs): 23000-25000 pairs on Steep Island and 7000-8000 pairs on the Doughboys. Little Penguin (10,000 pairs): 2000-3000 pairs on Steep Island, 3000 pairs on Bird Island, 2059 pairs on Three Hummock Island and 500 pairs on Trefoil Island. 1000 pairs White-faced Storm-Petrel reported on Penguin Islet. Records of Lewin's Rail at Trefoil and Hunter Islands are noteworthy, when the decline of the endemic Tasmanian race brachipus gives cause for serious concern. Nine pairs of Australian Pelican have bred on Penguin Islet; the islet is one of the few breeding sites for this species in Tasmania. Brothers et al. (2001) recorded small numbers of Fairy Tern, consisting of one pair feeding at Bird Island, one pair breeding at Stack Island and two individuals in flight over Seacrow Islet; and also small numbers of Hooded Plover on Stack Island (pairs and parties of up to five), Three Hummock Island (14 breeding pairs) and Seacrow Islet.

Non-bird biodiversity: Metallic Skink, White's Skink, Water Rat and Tiger Snake (irresponsibly introduced at Trefoil and Steep Islands, where potentially devastating to breeding seabirds).

Pressure/threats to key biodiversity
Cattle grazing needs to be regulated to maintain habitat suitability for Orange-bellied Parrot and seabirds. The impacts of long-line and net fishing, feral predators and invasive alien plants should be investigated. Some islands need up-graded protected area status.

Conservation responses/actions for key biodiversity
Viewing and landing at Nature Reserves should be by permit only, which would provide information on the number of visitors and thus contribute to the determination of sustainable visitor levels.

Protected areas
Five - see separate section for details.

Land ownership
The Doughboys, Three Hummock and Penguin Islands are Nature Reserves; Steep Island and Trefoil Island are owned by the Tasmanian Aboriginal community; Hunter Island is a Conservation Area with a private pastoral lease; Stack Island, Bird Island and others are Game Reserves.

Site access / Land-owner requests
Permission for access must be sought from the owners or DPIW.

The nomination was prepared by Peter Britton. Mark Holdsworth, Rachael Alderman and Rosemary Gales of DPIW kindly commented on the nomination.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Hunter Island Group. Downloaded from on 30/09/2023.