email a friend
printable version
Location Australia, Tasmania
Central coordinates 144o 49.74' East  40o 28.76' South
IBA criteria A1, A2, A3, A4i, A4ii
Area 15,236 ha
Altitude 0 - 237m
Year of IBA assessment 2009

BirdLife Australia

Summary The IBA supports more than 1% of the world population of Cape Barren Goose, Short-tailed Shearwater, Black-faced Cormorant, Sooty Oystercatcher and Pacific Gull. It also supports the critically endangered Orange-bellied Parrot on migration between Tasmania and mainland south-eastern Australia. Most of Tasmania's endemic forest birds breed in the IBA.

Site description 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).

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Cape Barren Goose Cereopsis novaehollandiae resident  1989-2007  500 individuals  A4i  Least Concern 
Short-tailed Shearwater Ardenna tenuirostris resident  1995  1,309,169-1,343,618 breeding pairs  A4ii  Least Concern 
Black-faced Cormorant Phalacrocorax fuscescens resident  1999  190 breeding pairs  A4i  Least Concern 
Tasmanian Native-hen Tribonyx mortierii resident  present  A2, A3  Least Concern 
Sooty Oystercatcher Haematopus fuliginosus resident  1982-1999  202 breeding pairs  A4i  Least Concern 
Pacific Gull Larus pacificus resident  1995  205 breeding pairs  A4i  Least Concern 
Green Rosella Platycercus caledonicus resident  unknown  A2, A3  Least Concern 
Orange-bellied Parrot Neophema chrysogaster non-breeding  unknown  A1, A3  Critically Endangered 
Yellow-throated Honeyeater Lichenostomus flavicollis resident  unknown  A2, A3  Least Concern 
Black-headed Honeyeater Melithreptus affinis resident  unknown  A2, A3  Least Concern 
Scrubtit Acanthornis magna resident  unknown  A2, A3  Least Concern 
Tasmanian Scrubwren Sericornis humilis resident  unknown  A2, A3  Least Concern 
Tasmanian Thornbill Acanthiza ewingii resident  unknown  A2  Least Concern 
Black Currawong Strepera fuliginosa resident  unknown  A2, A3  Least Concern 
Dusky Robin Melanodryas vittata resident  unknown  A2, A3  Least Concern 

IBA Monitoring

2008 high not assessed not assessed
Medium - based upon reliable but incomplete / partially representative data

Agriculture and aquaculture livestock farming and ranching (includes forest grazing) - agro-industry grazing, ranching or farmin happening now some of area/population (10-49%) slow but significant deterioration medium
Biological resource use fishing & harvesting aquatic resources - unintentional effects: large scale happening now some of area/population (10-49%) no or imperceptible deterioration low
Biological resource use hunting & collecting terrestrial animals - intentional use (species being assessed is the target) happening now small area/few individuals (<10%) no or imperceptible deterioration low
Invasive & other problematic species, genes & diseases invasive non-native/alien species/diseases - named species happening now small area/few individuals (<10%) slow but significant deterioration low
Natural system modifications fire & fire suppression - trend unknown/unrecorded happening now majority/most of area/population (50-90%) slow but significant deterioration high

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Bird Island Game Reserve 65 protected area contained by site 65  
Hunter Island Conservation Area 7,330 protected area contained by site 7,330  
Penguin Islet Nature Reserve 4 protected area overlaps with site 3  
Stack Island Game Reserve 30 protected area contained by site 30  
Three Hummock Island State Reserve 7,284 protected area contained by site 7,284  


IUCN habitat Habitat detail Extent (% of site)
Artificial - terrestrial Improved grassland & pasture  major
Coastline Sea cliffs, rocky shores & rocky islets  major
Forest Eucalypt open forests  minor
Grassland Tussock grasslands  minor
Shrubland Closed shrublands & low closed woodlands  major

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.

Land use

Land-use Extent (% of site)
nature conservation and research major
rangeland/pastureland major
Notes: cattle grazing
other minor
Notes: Traditional

Protection status Five - see separate section for details.

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

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

References Brothers, N., Pemberton, D., Pryor, H. and Halley, V. (2001) Tasmania's Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery: Hobart.

Hocking, G. (2007) Personal communication on Cape Barren Geese at Three Hummock and Hunter Islands, 1989-2007.

Skira, I.J., Brothers, N.P. and Pemberton, D. (1996) Distribution, abundance and conservation status of Short-tailed Shearwaters Puffinus tenuirostris in Tasmania. Marine Ornithology 24: 1-14.

Contribute  Please click here to help BirdLife conserve the world's birds - your data for this IBA and others are vital for helping protect the environment.

Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Hunter Island Group. Downloaded from on 25/10/2016

To provide new information to update this factsheet or to correct any errors, please email BirdLife