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LC
Brown Noddy Anous stolidus

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). The population trend appears to be stable, and hence the species does not 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 Noddy is a tropical seabird with a worldwide distribution, ranging from the Hawaiian Islands (USA) to the Tuamotu Archipelago (French Polynesia) and Australia in the Pacific Ocean, including colonies off the Pacific coast of north-west South and Central America, from the Red Sea to the Seychelles and Australia in the Indian Ocean including south-east Asia and in the Caribbean to Tristan da Cunha (St Helena to UK) in the Atlantic Ocean including a colony off the coast of Cameroon. Some colonies are also present in the sub-tropics with individuals from these colonies wintering in the tropics (del Hoyo et al. 1996).

Population justification
The global population is estimated to number c.180,000-1,100,000 individuals (Wetlands International 2006), while national population sizes have been estimated at c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Taiwan and c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Japan (Brazil 2009).

Trend justification
Although Wetlands International consider the population trend to be unknown, the population is suspected to be stable in the absence of evidence for any declines or substantial threats.

Ecology
Behaviour Although its migratory movements are poorly known and the species is present all year round at most tropical colonies, it is seasonally absent from subtropical colonies and is known to disperse to the open ocean after breeding (del Hoyo et al. 1996). The timing of breeding varies throughout the species's range (del Hoyo et al. 1996). It may breed colonially in groups numbering up to 100,000 or more pairs (Higgins and Davies 1996) although it also nests almost solitarily depending on the availability of nesting sites (del Hoyo et al. 1996). Even when not breeding the species remains gregarious and can occur in huge flocks in some areas, although it is more usually observed in smaller flocks of 50-100 individuals (Higgins and Davies 1996). Habitat The species occurs around isolated, bare or vegetated, pantropical and subtropical, inshore or oceanic islands or coral reefs with rocky cliffs or offshore stacks (del Hoyo et al. 1996) and coral or sand beaches (Higgins and Davies 1996). It forages in the inshore waters surrounding such islands, often along the line of breakers or in lagoons (Higgins and Davies 1996), and disperses up to 50 km out into the pelagic zone to forage (del Hoyo et al. 1996) (especially when not breeding) (Higgins and Davies 1996). Out at sea it often rests on buoys, flotsam, ships and on the open water (del Hoyo et al. 1996). Diet Its diet consists predominantly of small fish (Higgins and Davies 1996) as well as squid (del Hoyo et al. 1996), pelagic molluscs, medusae and insects (Higgins and Davies 1996). Breeding site The nest may be a simple layer of debris or a more elaborate construction of seaweed and sticks (del Hoyo et al. 1996), and may be placed in a number of sites including flat shingle beaches, bare ground, cliff ledges, offshore stacks, low bushes and tall trees (del Hoyo et al. 1996). It nests in colonies that can be very dense or more open depending on the availability of nesting sites (del Hoyo et al. 1996).

Threats
Breeding colonies on islands (e.g. Ascension Island) are threatened by predation from introduced rats and cats (del Hoyo et al. 1996). Predation from the introduced brown tree snake Boiga irregularis is also likely to havecaused the decline in the breeding population on Guam (Reichel 1991). Utilisation Eggs, chicks and adults (to a lesser extent) are taken from breeding colonies in the Mariana Islands (Reichel 1991).

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

del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

Higgins, P. J.; Davies, S. J. J. F. 1996. Handbook of Australian, New Zealand and Antarctic birds vol 3: snipe to pigeons. Oxford University Press, Oxford.

Reichel, J. D. 1991. Status and conservation of seabirds in the Mariana Islands. In: Croxall, J.P. (ed.), Seabird status and conservation: a supplement, pp. 249-262. International Council for Bird Preservation, Cambridge, U.K.

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

View photos and videos and hear sounds of this species from the Internet Bird Collection

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

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

Recommended citation
BirdLife International (2014) Species factsheet: Anous stolidus. Downloaded from http://www.birdlife.org on 23/10/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/10/2014.

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 noddy (Anous stolidus) 0

Key facts
Current IUCN Red List category Least Concern
Family Laridae (Gulls, Terns, Skimmers)
Species name author (Linnaeus, 1758)
Population size mature individuals
Population trend Stable
Distribution size (breeding/resident) 26,800 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change