|Central coordinates||143o 7.28' East 11o 30.24' South|
|IBA criteria||A4i, A4ii|
|Altitude||0 - 46m|
|Year of IBA assessment||2009|
Summary These 10 seabird islands (or island groups) have supported more than 1% of the world population of Pied Imperial-Pigeon, Roseate Tern, Lesser Crested Tern, Bridled Tern and Grey-tailed Tattler.
Site description This IBA (~215 ha in total) consists of a string of 10 important seabird islands or island groups in the northern Great Barrier Reef, from Womer Cay opposite the tip of Cape York to the Sir Charles Hardy Islands opposite Cape Grenville. All islands which have a record of more than 1% of the world population of any seabird are listed in the IBA. There have been insufficient survey visits on most islands to determine whether they regularly support these numbers of seabirds and whether other neighbouring islands also qualify; moreover, many seabirds are naturally irregular and sometimes aseasonal in their breeding. There are numerous other islands within this IBA and to the north and south. With the exception of the Sir Charles Hardy Islands (1 & 2), the islands are small low level sandy cays with variable amounts of harder coralline substrates, grass, herbs and vines, and some larger islands have Pisonia grandis trees. The islands included in the IBA are: Womer Cay (1 ha; 1000 pairs Lesser Crested Tern in 1998), Cairncross Island (2 ha; 2000 nests Pied Imperial-Pigeon in 2002), Douglas Island (2 ha; 5250 pairs Black Noddy in 1988), Cholmondeley Islet (0.5 ha; 830 Roseate Tern chicks in 1982 and 600 adults in 1986; 590 nests Crested Tern and 162 pairs Lesser Crested Tern in 1985), Boydong Island (4 ha; 1150 Grey-tailed Tattler in 1999 and over 400 in 1985 and 1987), Wallace Islet (2.2 ha; 1000 chicks of Roseate Terns in 1976 and 5000 pairs in 1986; 300 pairs Bridled Tern in 2002), Hannibal Islands (10 ha; 24,400 pairs of Pied Imperial-Pigeon), Saunders Islet (9.4 ha; 6000 pairs Roseate Tern in 1995 but often smaller numbers), Magra Islet (2.7 ha; 2700-3100 pairs Roseate Tern in 1992-1993 and 5000 adults in 2002 but only 400 adults in 1981) and the Sir Charles Hardy Islands (182 ha; 6000 pairs of Bridled Tern in 1988). The Sir Charles Hardy Islands are two large rocky islands with a sandy fringe; they are the largest and the tallest (46 m above sea level) island group captured by the IBA and constitute 84% of the total area of the IBA. Other islands with near-threshold or old counts include Bird Islands (4000+ pairs Black Noddy in 1975). All the islands are in the Marine National Park except for Cairncross Island; all the surrounding seas are in the Marine National Park except for waters around Cairncross Island and Magra Islet, which are in the general use zone of the Great Barrier Reef Marine Park.
Key Biodiversity Other birds have not been documented for this IBA.
Non-bird biodiversity: Green and Hawksbill Turtles.
|Species||Season||Period||Population estimate||Quality of estimate||IBA Criteria||IUCN Category|
|Grey-tailed Tattler Tringa brevipes||non-breeding||1985-1999||1,150 individuals||-||A4i||Near Threatened|
|Lesser Crested Tern Thalasseus bengalensis||resident||1982-1992||1,000 nests||-||A4i||Least Concern|
|Roseate Tern Sterna dougallii||resident||1982-1992||6,000 nests||-||A4i||Least Concern|
|Bridled Tern Onychoprion anaethetus||resident||1982-1992||6,000 nests||-||A4i||Least Concern|
|Torresian Imperial-pigeon Ducula spilorrhoa||resident||1979-2002||24,397 breeding pairs||-||A4ii||Least Concern|
|2008||high||not assessed||not assessed|
|Medium - based upon reliable but incomplete / partially representative data|
|Climate change and severe weather||storms and floods||likely in long term (beyond 4 years)||whole area/population (>90%)||moderate to rapid deterioration||high|
|Human intrusions and disturbance||recreational activities||happening now||small area/few individuals (<10%)||no or imperceptible deterioration||low|
|Protected area||Designation||Area (ha)||Relationship with IBA||Overlap with IBA (ha)|
|Denham Group||National Park||91||protected area overlaps with site||62|
|Great Barrier Reef||World Heritage Site||34,870,000||protected area contains site||210|
|Saunders Islands||National Park||19||protected area contained by site||19|
|Sir Charles Hardy Group||National Park||129||protected area contained by site||129|
|IUCN habitat||Habitat detail||Extent (% of site)|
|Coastline||Sand cays, islets & bars||100%|
Land ownership Commonwealth Government with management the responsibility of the GBRMPA.
|Land-use||Extent (% of site)|
|nature conservation and research||100%|
Protection status The IBA overlaps with four protected areas including the Great Barrier Reef World Heritage Area.
Acknowledgements Paul O'Neill provided advice and access to the GBR seabird database.
References GBRMPA (1997) Guidelines for Managing Visitation to Seabird Breeding Islands. Unpublished report. Great Barrier Reef Marine Park Authority.
King, B.R. (1989) Magra Island, Great Barrier Reef, Queensland. Corella 13: 47-48.
King, B.R., Hicks, J. and Oldroyd, A. (1989) Cholmondeley Island, Great Barrier Reef, Queensland. Corella 13: 41-42.
King, B.R. and Limpus, C.J. (1989) Saunders Island, Great Barrier Reef, Queensland. Corella 13: 45-46.
King, B.R., Limpus, C.J, Hicks, J. and Oldroyd, A. (1989) Wallace Island, Great Barrier Reef, Queensland. Corella 13: 43-44.
Higgins, P.J. and Davies, S.J.J.F., eds (1996) Handbook of Australian, New Zealand and Antarctic Birds. Volume 6: Snipe to Pigeons. Melbourne: Oxford University Press.
Queensland Parks & Wildlife Service (2007) GBR seabird database (accessed May 2007).
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Recommended citation BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Cape York to Cape Grenville Islands. Downloaded from http://www.birdlife.org on 24/05/2016
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