This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
Sula dactylatra (AOU 1998 + updates) and Sula tasmani (Christidis and Boles 1994) have been lumped as S. dactylatra following Christidis and Boles (2008).
Related state of the world's birds case studies
AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.
Christidis, L. and Boles, W.E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
Christidis, L.; Boles, W. E. 1994. The taxonomy and species of birds of Australia and its territories. Royal Australasian Ornithologists' Union, Melbourne.
del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.
IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: www.iucnredlist.org. (Accessed: 19 November 2015).
Further web sources of information
Click here to read about RSPB's work with Masked Boobies on Ascension Island
Text account compilers
Butchart, S., Calvert, R. & Ekstrom, J.
IUCN Red List evaluators
Butchart, S. & Symes, A.
BirdLife International (2016) Species factsheet: Sula dactylatra. Downloaded from http://www.birdlife.org on 01/06/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 01/06/2016.
This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.
To provide new information to update this factsheet or to correct any errors, please email BirdLife
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Additional resources for this species
|Current IUCN Red List category||Least Concern|
|Family||Sulidae (Gannets, Boobies)|
|Species name author||Lesson, 1831|
|Population size||mature individuals|
|Distribution size (breeding/resident)||102,000 km2|
|Links to further information|
|- Additional Information on this species|