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Location Australia, Northern Territory
Central coordinates 136o 42.12' East  12o 50.60' South
IBA criteria A4i
Area 190 ha
Altitude 0 - 10m
Year of IBA assessment 2009

BirdLife Australia



Summary The Three Hummocks Islands are a group of small granite islands with very large numbers of Bridled Terns nesting on the four largest islands. Smaller numbers of Roseate Terns have also been recorded nesting on adjacent islands.

Site description The Three Hummocks Island group is south of Wanyanmera Point in north-east Arnhem Land. They are a group of partially vegetated granite island with large numbers of Bridled Terns nesting on the four largest islands. The IBA also includes the nearby rocky and sandy Dudley Island to the south and a number of unnamed rocky islets to the north. These are island refs S038, S039, S041, S104 and S105 in Chatto (2001).

Key Biodiversity Chatto (2001) made nine counts on the Three Hummocks Island group. The estimated numbers of Bridled Terns nesting in the four years between 1993-1999 when counts were made were 10,000, 5000, 7500 and 20,000-50,000. On the small islands to the north, up to 500 Roseate Terns and 450 Black-naped Terns were recorded as irregularly nesting. On Dudley Island to the south, up to 300 Black-naped, 200 Bridled and 200 Roseate Terns have been recorded nesting.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Bridled Tern Onychoprion anaethetus breeding  1990-2000  20,000-50,000 individuals  medium  A4i  Least Concern 

IBA Monitoring

2008 low not assessed not assessed
unset
Poor - based on little, or potentially unreliable/unrepresentative, data

No known threats no known threats happening now small area/few individuals (<10%) no or imperceptible deterioration low

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Laynhapuy Indigenous Protected Area 450,000 protected area overlaps with site 112  

Habitats

IUCN habitat Habitat detail Extent (% of site)
Coastline Sea cliffs, rocky shores & rocky islets  major

Land ownership Arnhem Land ALT

Land use

Land-use Extent (% of site)
other major
Notes: Traditional use

Protection status There is an overlap with the Laynhapuy Indigenous Protected Area.

Access/Land-Owner requests Traditionally-owned land.

References Chatto, R. (2001) The distribution and status of colonial breeding seabirds in the NT. Technical Report 70. Parks and Wildlife Commission of the Northern Territory, Palmerston. Harrison, L., McGuire, L., Ward, S. Fisher, A., Pavey, C., Fegan, M. and Lynch, B. (2009) An inventory of sites of international and national significance for biodiversity values in the Northern Territory. Department of Natural Resources, Environment, the Arts & Sport, Darwin, NT. Ward, S. and Harrison, L. (2009) Recognising sites of conservation significance for biodiversity values in the Northern Territory. Department of Natural Resources, Environment, the Arts & Sport, Darwin, NT.

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Three Hummocks Island. Downloaded from http://www.birdlife.org on 26/12/2014

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