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Inca Tern Larosterna inca
BirdLife is updating this factsheet for the 2016 Red List
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This species is listed as Near Threatened because its population has apparently experienced a moderately rapid decline.

Taxonomic source(s)
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: #

41cm. It can be identified by its dark grey body, white moustache on both sides of its head, and red-orange beak and feet. Juveniles lack moustache and have brown plumage and bare parts. Similar species: Adults unmistakeable, juveniles could be mistaken for noddy sps.

Distribution and population
Larosterna inca is found along the Pacific coast from northern Peru south to central Chile. Mass dispersal and breeding failures have resulted periodically from El Niño Southern Oscillation (ENSO) events, and both fish-stocks and the populations of seabirds that depend upon them are adapted to these fluctuations. Population declines are usually promptly reversed, suggesting that food shortages trigger rapid dispersal not high mortality in adults and high reproduction rates (up to two successful broods in a year). Although fishing for anchoveta has been banned in Peru, and the guano industry adequately regulated, there are concerns that this species might be badly affected by the El Niño Southern Oscillation event of 1998 (G. Engblom in litt. 2003). Prior to the guano industry (c.1850) there were millions of Inca Terns in Peru (according to accounts from Coker 1919, Hutchison 1950). Current numbers are much lower than two centuries ago, but they are common and breed in some localities. The total population has been estimated at more than 150,000 individuals (Zavalaga et al. unpublished data).

Population justification
The total population has been estimated more than 150,000 individuals (Zavaga et al. unpublished data).

Trend justification
Survey data suggest that moderately rapid declines have occurred.

It breeds on inshore (and occasionally offshore) islands and rocky coastal cliffs. Nests are placed in suitable fissures, burrows, caves and cavities, sometimes the old nest of a Humboldt Penguin Spheniscus humboldti. It feeds, often in large flocks, on schooling anchoveta Engraulis ringens, mote sculpins Normanychtic crokeri and silversides Odothestes regia regia found in the cold water of the Humboldt Current. Additionally, this species scavenges offal and scraps from sea-lions and fishing boats. One or two eggs are incubated for about four weeks, and the chicks leave the nest after seven weeks. Birds feed by plunge diving for fish.

Reduction of nesting habitat as a result of guano harvesting may affect population dynamics. However, Inca Terns are very flexible and successful in using any kind of coverage (natural or artificial) for nesting. They can nest inside abandoned buildings and huts on guano islands, and in any pile of wood and metal slabs. Reduction of anchovy stocks due to commercial fishing may limit population size. The presence of rats and cats on some islands can also prevent nesting or reduce breeding success.

Conservation Actions Underway
Some breeding sites lie within managed guano reserves or protected areas. Conservation Actions Proposed
Identify those breeding sites where introduced predators are a problem and control/remove them from these sites. Determine effects of interactions with fisheries. Monitor population levels at key sites. Establish key locations as Marine Protected Areas.

Coker, R. C. 1919. Habits and economic relations of the guano birds of Peru. Proceedings of the United States National Museum 56: 449-511.

del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. 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
Benstead, P., Butchart, S., Frere, E., Lascelles, B., Sharpe, C J

Engblom, G., Zavalaga, C.

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

Recommended citation
BirdLife International (2016) Species factsheet: Larosterna inca. Downloaded from on 26/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 26/10/2016.

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

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 - Inca tern (Larosterna inca) 0

Key facts
Current IUCN Red List category Near Threatened
Family Laridae (Gulls, Terns, Skimmers)
Species name author (Lesson, 1827)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 477,000 km2
Country endemic? No
Links to further information
- Additional Information on this species