Sternula lorata 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae

Scientific Name: Sternula lorata (Philippi & Landbeck, 1861)
Common Name(s):
English Peruvian Tern
Spanish Charrancito Peruano
Sterna lorata Philippi & Landbeck, 1861
Taxonomic Source(s): SACC. 2005 and updates. A classification of the bird species of South America. Available at: #
Taxonomic Notes: Sternula lorata (del Hoyo and Collar 2014) was previously placed in the genus Sterna.

Assessment Information [top]

Red List Category & Criteria: Endangered C2a(i) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Engblom, G., Guerra, C., Jaramillo, A., Plenge, M., Tello, A. & Zavalaga, C.
Facilitator/Compiler(s): Anderson, O., Benstead, P., Calvert, R., Capper, D., Frere, E., Harding, M., Khwaja, N., Lascelles, B., Moreno, R., Sharpe, C.J., Symes, A.
This species is listed as Endangered because it is estimated to have a very small population which is undergoing continuing declines owing to habitat loss and disturbance on its breeding grounds. It is also restricted to a very small area when breeding and these breeding grounds remain highly threatened.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Sternula lorata is restricted to the Humboldt Current Zone from north Peru to the peninsula of Mejillones in Chile (Enticott and Tipling 1997, Guerra-Correa et al. 2007). Its movements are poorly known, but it has been recorded north to central Ecuador (Enticott and Tipling 1997). There are now only four confirmed breeding sites in Peru, at Pampa Lechuzas, Yanyarina, Paraiso and Pacasmayo (Zavalaga et al. 2008a), and nine in Chile, all of which are located in Mejillones and nearby areas (Guerra-Correa et al. 2007). In Chile all colonies have been found in the desert plains, generally within 1 km of the coast, but in other locations colonies have also been found on sandy beaches associated with wetlands. A well-known former breeding site at Puerto Viejo is now heavily developed and no longer supports breeding birds (Zavalaga et al. 2008a), and population declines have been noted at Pampa Mejillones and La Portada in Chile. One locality was previously reported to have tens of thousands of individuals, but the population is now thought to be significantly reduced, as the numbers at all sites are estimated at 950-1,100 individuals and 150 to 160 pairs (Guerra-Correa et al. 2007). Some reports suggest that the population may have declined by 50% in the last 10 years (Luchsinger 2007). However, there are still unsurveyed sandy beaches away from the Pan-American Highway that could be suitable for nesting, and old colonies that have not been visited since their discovery decades ago, while signs of previously unknown breeding sites have recently been recorded in La Libertad, Peru (Amorós 2011); the total is therefore likely to fall in the range of 1,000-2,500 individuals.

Countries occurrence:
Chile; Ecuador; Peru
Additional data:
Estimated area of occupancy (AOO) - km2:21Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:67600
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:6-10Continuing decline in number of locations:Yes
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Estimates range from 100 pairs (G. Engblom in litt. 2005) to 5,000 pairs (M. Plenge in litt. 1999). Given that there are still unsurveyed sandy beaches away from the Pan-American Highway, the total is perhaps likely to fall in the range of 1,000-2,499 individuals. This equates to 667-1,666 mature individuals, rounded to 600-1,700 individuals here.

Trend Justification:  Suspected to be declining on the basis of continued destruction, degradation of its breeding habitat, disappearance of breeding colonies in the last 30 years (e.g. Puerto Viejo and Mollendo in Peru) and population decline in some localities (Pampa Mejillones and La Portada in Chile).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:600-1700Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:2-100Continuing decline in subpopulations:Yes
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:1-89

Habitat and Ecology [top]

Habitat and Ecology:It breeds either on broad sandy beaches and dunes (100-200 m from the high tide mark) associated with wetlands (Zavalaga et al. 2008a), or in desert plains 1-3 km inland (Vilina 1998, Guerra et al. 2003, Zavalaga et al. 2008a). The shallow waters of wetlands are thought to offer optimal conditions for foraging, both within and outside the breeding season (Zavalaga et al. 2009). Egg-laying is asynchronous both within and between groups, and spread from August to February (Vilina 1998, Guerra et al. 2003), particularly October to late January (Zavalaga et al. 2008b).Clutch size is one or two eggs, but usually only one chick fledges (Vilina 1998, Guerra et al. 2003). To counteract high levels of predation it nests in homogeneous habitat in small groups (3-25 nests), loosely aggregated, with inter-nest distances usually over 100 m (Vilina 1998, Zavalaga et al. 2008b), thus making nests difficult to detect (Zavalaga et al. 2008a). Eggs and chicks are well camouflaged with the bare ground. Inland nesting is believed to be a strategy to reduce risk from terrestrial predation, as predators often patrol closer to the shore. Birds are known to be absent during El Niño events (Zavalaga et al. 2008a) and do not attempt to breed (Zavalaga et al. 2008b). Post-breeding dispersal occurs from April until July, to unknown areas, probably offshore (Mackiernan et al. 2001). During the 1997-1998 El Niño event, hundreds were sighted 25-200 km offshore, suggesting they can disperse widely during oceanographic anomalies (Zavalaga et al. 2008a). It generally forages in inshore areas, but is occasionally seen 10-70 km offshore (Mackiernan et al. 2001). Main prey include anchovies Engraulis ringens, South Pacific sauris Scomberesox saurus scombroides (Guerra et al. 2003), Peruvian silversides Odonthestes regia regia and mote sculpins Normanychtis crockeri. Prey items found in nests measured less than 8 cm, indicating a prey size limit imposed by chick body size (Zavalaga et al. 2008b).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):9
Movement patterns:Not a Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): It undoubtedly suffered from the 1972 collapse of anchoveta Engraulis spp. stocks. which have not subsequently recovered (Schlatter 1984, Gochfeld and Burger 1996). The principle threat to this species is the destruction of breeding habitat, through building of shanty towns, summer homes (as at Puerto Viejo), road constructions and through human activities such as driving 4×4 vehicles on the beaches. Off-road vehicles have also led to increased disturbance in previously inaccessible areas. Other threats include wetland pollution and water use for irrigation (at Paraiso and Mejia), conversion of desert plains into agricultural land (at Punta Literas-Pativilca), management of wetland water levels (at Ite) and oil exploration near tern areas (at San Pedro de Vice). In Chile, risks include the building of port facilities at Mejillones (which would affect at least 200 birds), off-road driving at Rio Loa and the construction of coastal highways throughout the north (Guerra-Corre et al. 2007). Foxes Pseudalopex spp. and aerial raptors are considered the main predators of Peruvian Tern (Vilina 1998, Guerra et al. 2003, Zavalaga et al. 2009).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
In Chile, CONAMA (2006) has recognized the species as threatened with extinction, and it has been officially classified as Endangered. In Peru it has been recognized as Vulnerable (Zavalaga et al. 2008a).

Conservation Actions Proposed
Conduct searches for colonies in previously unsurveyed areas or in areas that need confirmation of breeding (Chavez 2007). Monitor known colonies to assess trends. Restore abandoned colonies using decoys and playbacks. Uplist the conservation status in Peru from Vulnerable to Endangered and include monthly evaluations for the presence of terns in any project for the construction of roads or other facilities in coastal desert plains (up to 5 km inland). Protect known colonies from habitat destruction, disturbance and pollution.

Citation: BirdLife International. 2016. Sternula lorata. The IUCN Red List of Threatened Species 2016: e.T22694685A93462855. . Downloaded on 23 September 2018.
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