Larosterna inca


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Larosterna inca
Species Authority: (Lesson, 1827)
Common Name(s):
English Inca Tern

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Engblom, G. & Zavalaga, C.
Facilitator/Compiler(s): Benstead, P., Butchart, S., Frere, E., Lascelles, B., Sharpe, C J
This species is listed as Near Threatened because its population has apparently experienced a moderately rapid decline.

Geographic Range [top]

Range Description: 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 unpublished data).

Chile; Colombia; Ecuador; Peru
Range Map: Click here to open the map viewer and explore range.

Population [top]

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 unpublished data).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

Habitat and Ecology [top]

Habitat and Ecology: 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.

Systems: Terrestrial; Marine

Threats [top]

Major Threat(s): 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 [top]

Conservation Actions: 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.

Citation: BirdLife International 2012. Larosterna inca. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 02 September 2015.
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