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.

Family/Sub-family Laridae

Species name author (Linnaeus, 1758)

Taxonomic source(s) AERC TAC (2003), AOU checklist (1998 + supplements), Christidis and Boles (1994), Christidis and Boles (2008), Cramp and Simmons (1977-1994), Dowsett and Forbes-Watson (1993), SACC (2005 + updates), Sibley and Monroe (1990, 1993), Stotz et al. (1996), Turbott (1990)

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

180,000 - 1,100,000

unset

-

No

Range & 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 tropics¹.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

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 breeding¹. The timing of breeding varies throughout the species's range¹. It may breed colonially in groups numbering up to 100,000 or more pairs² although it also nests almost solitarily depending on the availability of nesting sites¹. 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 individuals². Habitat The species occurs around isolated, bare or vegetated, pantropical and subtropical, inshore or oceanic islands or coral reefs with rocky cliffs or offshore stacks¹ and coral or sand beaches². It forages in the inshore waters surrounding such islands, often along the line of breakers or in lagoons², and disperses up to 50 km out into the pelagic zone to forage¹ (especially when not breeding)². Out at sea it often rests on buoys, flotsam, ships and on the open water¹. Diet Its diet consists predominantly of small fish² as well as squid¹, pelagic molluscs, medusae and insects². Breeding site The nest may be a simple layer of debris or a more elaborate construction of seaweed and sticks¹, and may be placed in a number of sites including flat shingle beaches, bare ground, cliff ledges, offshore stacks, low bushes and tall trees¹. It nests in colonies that can be very dense or more open depending on the availability of nesting sites¹.

Threats Breeding colonies on islands (e.g. Ascension Island) are threatened by predation from introduced rats and cats¹. Predation from the introduced brown tree snake Boiga irregularis is also likely to have caused the decline in the breeding population on Guam³. Utilisation Eggs, chicks and adults (to a lesser extent) are taken from breeding colonies in the Mariana Islands³.

References 1. del Hoyo et al. (1996). 2. Higgins and Davies (1996). 3. Reichel (1991).

Text account compilers Stuart Butchart (BirdLife International), Rob Calvert (BirdLife International), Jonathan Ekstrom (BirdLife International), Lucy Malpas (BirdLife International)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International)

Recommended citation BirdLife International (2010) Species factsheet: Anous stolidus. Downloaded from http://www.birdlife.org on 30/7/2010

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.

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