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Location Australia, Queensland
Central coordinates 145o 58.76' East  16o 36.31' South
IBA criteria A4i
Area 2 ha
Altitude 0 - 4m
Year of IBA assessment 2008

BirdLife Australia

Summary Michaelmas Cay is a well-studied island off Cairns which has supported more than 1% of the world population of Crested Tern and Lesser Crested Tern.

Site description Michaelmas Cay is about 40 km east of Cairns in the northern Great Barrier Reef. It is a vegetated sand cay, and covered about 360 m x 50 m in 1984, but is subject to erosion and accretion. The cay is comprised of coral sand with low mats of grasses and herbs, which vary in extent between seasons. It is zoned as a Marine National Park, allowing boat limited visits and diving.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Lesser Crested Tern Thalasseus bengalensis resident  1982-1992  1,000-1,623 nests  A4i  Least Concern 
Greater Crested Tern Thalasseus bergii resident  1982-1992  2,000-6,080 nests  A4i  Least Concern 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Michaelmas and Upolu Cays National Park 3 protected area overlaps with site 2  


IUCN habitat Habitat detail Extent (% of site)
Coastline Sand cays, islets & bars  100%

Land ownership Australian Federal Government with management the responsibility of GBRMPA.

Land use

Land-use Extent (% of site)
nature conservation and research 100%

Protection status The IBA overlaps with Michaelmas and Upolu Cays National Park.

Acknowledgements Paul O'Neill provided advice and access to the GBR seabird database and the nomination was prepared in consultation with Mike Short.

References GBRMPA. (1997) Guidelines for Managing Visitation to Seabird Breeding Islands. Great Barrier Reef Marine Park Authority unpublished report.

King, B.R. (1985) Michaelmas Cay, Great Barrier Reef, Queensland. Corella 9: 94-96. Queensland Parks & Wildlife Service (2007) GBR seabird database (accessed May 2007).

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Michaelmas Cay. Downloaded from on 19/09/2014

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