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Brown Booby Sula leucogaster

Justification
This species has an extremely 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 is very large, and hence does not 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.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
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.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Distribution and population
The Brown Booby can be found throughout the pantropical oceans with few exceptions. Breeding sites include the Carribean, the Atlantic coasts of Brazil and Africa, oceanic islands off Madagascar, the Red Sea, northern Australia, many oceanic islands in the western and central Pacific, as well as off the coast of Mexico and Peru1

Population justification
The global population is estimated to number > c.200,000 individuals (del Hoyo et al. 1992), while national population sizes have been estimated at c.10,000-100,000 breeding pairs and c.1,000-10,000 individuals on migration in Taiwan and c.10,000-100,000 breeding pairs, c.1,000-10,000 individuals on migration and c.1,000-10,000 wintering individuals in Japan (Brazil 2009).

Trend justification
The population is suspected to be in decline owing to disturbance and unsustainable levels of exploitation.

Ecology
This species is strictly marine, generally feeding on inshore waters. Its diet is comprised mainly of flying-fish and squid, but also some halfbeak (Hemiramphu), mullet (Mugil) and anchovy (Engraulis). Prey is usually caught by plunge-diving and it can also snatch prey off the surface of water. Kleptoparasitism has been observed, mostly by females. Breeding is seasonal in some reas by elsewhere it breeds opportunistically or more or less continuously. Nests are usually built on the ground in the midst of vegetation on rocky islands or coral atolls. Individuals form colonies that are usually smaller than other Sula species (del Hoyo et al. 1992).

Related state of the world's birds case studies

References
Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.

del Hoyo, J.; Elliot, A.; Sargatal, J. 1992. Handbook of the Birds of the World, vol. 1: Ostrich to Ducks. Lynx Edicions, Barcelona, Spain.

Further web sources of information
Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Ekstrom, J., Butchart, S., Calvert, R.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Sula leucogaster. Downloaded from http://www.birdlife.org on 02/09/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/09/2014.

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

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Brown booby (Sula leucogaster) 0

Key facts
Current IUCN Red List category Least Concern
Family Sulidae (Gannets, Boobies)
Species name author (Boddaert, 1783)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 26,600,000 km2
Country endemic? No
Links to further information
- Additional Information on this species