Sternula Lorata,: Assessment By: Birdlife International

The IUCN Red List of Threatened Species™
ISSN 2307-8235 (online)

IUCN 2008: T22694685A132567771
Scope: Global
Language: English
Sternula lorata, Peruvian Tern

Assessment by: BirdLife International
View on www.iucnredlist.org
Citation: BirdLife International. 2018. Sternula lorata. The IUCN Red List of Threatened Species
2018: e.T22694685A132567771. http://dx.doi.org/10.2305/IUCN.UK.2018-
2.RLTS.T22694685A132567771.en
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Taxonomy
Kingdom Phylum Class Order Family
Animalia Chordata Aves Charadriiformes Laridae
Taxon Name: Sternula lorata (Philippi & Landbeck, 1861)
Synonym(s):
• Sterna lorata Philippi & Landbeck, 1861
Common Name(s):
• English: Peruvian Tern
• Spanish: Charrancito Peruano
Taxonomic Source(s):
SACC. 2005 and updates. A classification of the bird species of South America. Available at:
#http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm#.
Taxonomic Notes:
Sternula lorata (del Hoyo and Collar 2014) was previously placed in the genus Sterna.
Assessment Information
Red List Category & Criteria: Endangered C2a(i) ver 3.1
Year Published: 2018
Date Assessed: August 7, 2018
Justification:
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

2016 – Endangered (EN)
http://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22694685A93462855.en

2004 – Near Threatened (NT)
© The IUCN Red List of Threatened Species: Sternula lorata – published in 2018. 1
2000 – Lower Risk/near threatened (LR/nt)
1994 – Lower Risk/least concern (LR/lc)
1988 – Lower Risk/least concern (LR/lc)
Geographic Range
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 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 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 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.
Country Occurrence:
Native: Chile; Ecuador; Peru
Distribution Map
Sternula lorata
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 here to 600-1,700 individuals.
Trend Justification
The population is suspected to be declining on the basis of continued destruction and degradation of
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
Habitat and Ecology (see Appendix for additional information)

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 occurs 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 items 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
Threats (see Appendix for additional information)

As a ground nesting species, the Peruvian Tern is vulnerable to human activities, which can cause
disturbance of nesting adults and a subsequent loss of reproductive success, as well as the loss and
degradation of vital nesting habitat. Local small scale harvesting of marine resources such as seaweed,
fish and shellfish has been recorded at multiple breeding and non-breeding sited (e.g. Pacasmayo and
Paraiso) and is associated with the use of 4x4 vehicles on the beach, introduction of dogs and
construction of small fishing camps (Zavalaga et al. 2008ab, Zavalaga et al. 2009). Similar disturbance
also occurs due to recreational activities such as off-road driving and dog walking, with disturbance
intensifying in Paraiso between 2003 and 2008 (Zavalaga et al. 2009). Feral Cats Felis catus were
recorded at multiple breeding sites in 2008, including Isla Lobos de Tierra and Tres Hermanas-Yanyarina
and have been seen to attack Peruvian Terns (Zavalaga et al. 2008a) and may deter settlement and
breeding (Zavalaga et al. 2009). Foxes Pseudolopex spp. have been recorded at almost all nesting sites
studies and are considered among the main predators of tern nests (Zavalaga et al. 2008ab, 2009). Well
known breeding sites have been lost to heavy residential development (Zavalaga et al. 2008a), including
the building of shanty towns and summer homes in Puerto Viejo as well as residential and commercial
development at Pampa de Mejillones, Northern Chile, causing a reduction in the breeding habitat
available to the largest colony of Peruvian Terns (Braby 2011). The expansion of tourist and recreational
areas is also a threat to breeding sites (Zavalaga et al. 2009). Conversion of desert plains into agricultural
land at nesting sites (e.g. Punta Literas-Pativilica) through the use of irrigation (Zavalaga et al. 2009)
represents a further loss of breeding habitat. Significant as only a handful of breeding sites known.
Abstraction for irrigation degrades wetland foraging habitat, with the construction of 1.5m sand dam at
the Ite site in 2008 increasing water levels in the area, possibly making it unsuitable for the terns, with
birds recorded in 2007 but not in 2008 (Zavalaga 2009). Oil exploration near tern nests at San Pedro de
Vice is likely to have destroyed possible nesting sites, as well as causing irreversible damage to
mangrove ecosystem which Peruvian Terns use to forage (Zavalaga et al. 2009). Further to this, breeding
success at nesting sites in 1980s El Niño Southern Oscillation (ENSO) event was reported to drop to 0%
at some sites, with breeding not attempted or chicks dying of starvation. This species has been
highlighted as being vulnerable to the impacts of ENSO due to the effects of decreased prey availability.
Conservation Actions (see Appendix for additional information)

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.
Credits
Assessor(s): BirdLife International
Reviewer(s): Wheatley, H.
Contributor(s): Engblom, G., Guerra, C., Jaramillo, A., Plenge, M., Tello, A. & Zavalaga, C.
Facilitators(s) and Anderson, O., Benstead, P., Calvert, R., Capper, D., Frere, E., Harding, M., Khwaja,
Compiler(s): N., Lascelles, B., Martin, R., Moreno, R., Palmer-Newton, A., Sharpe, C.J., Stuart,
A., Symes, A.
Bibliography
Amorós, S. 2011. Signs of new breeding sites for Peruvian Tern, Sternula lorata (Charadriiformes,
Laridae) at La Libertad, Peru, and its implications for conservation. The Biologist (Lima) 9(2): 177-192.
Braby, J. 2011. The conservation and biology of the Damara Tern in Namibia. University of Cape Town.
Chavez Villavencio, C. 2007. Las aves de Santuario de Conservacion Regional Manglares San Pedro de
Vice, Sechura, Peru. Cotinga 27: 32-37.
CONAMA (Conselho Nacional do Meio Ambiente). 2006. Plano Estratégico Nacional de Áreas Protegidas
- PNAP. Ministério do Meio Ambiente, Brasilia.
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife
International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions
BirdLife International, Barcelona, Spain and Cambridge, UK.
Enticott, J.; Tipling, D. 1997. Photographic handbook of the seabirds of the world. New Holland, London.
Guerra-Correa, C. 2007. Plan de recuperacion, manejo y conservacion para Gaviotín Chirrío (Chico)
Sterna lorata en el Norte de Chile. Centro Regional de Estudios y Educación Ambiental – Universidad de
Antofagasta. Ministerio de Energía – Gobierno de Chile, Antofagasta, Chile.
Guerra, P.A. de C., Rubira, C. and De Lemos, R. 2003. Springer, New York, USA.
IUCN. 2018. The IUCN Red List of Threatened Species. Version 2018-2. Available at: www.iucnredlist.org.
(Accessed: 15 November 2018).
Luchsinger F. 2007. Gaviotín en peligro. Diario "El Mercurio" Sábado 03 de Noviembre de 2007.
Mackiernan, G., Lonsdale, P., Shany, N., Cooper, B. and Ginsburg, P. 2001. Observations of seabirds in
Peruvian and Chilean waters during the 1998 El Nino. Cotinga 15: 88-94.
Vilina, Y. A. 1998. Breeding observations of the Peruvian Tern in Chile. Colonial Waterbirds 21: 101-103.
Zavalaga, C.B., Hardesty, J., Mori, G.P., Chavez-Villavicencio, C. and Tello, A. 2009. Current status of
Peruvian terns Sterna lorata in Peru: threats, conservation and research priorities. Bird Conservation
International 19(2): 175-186.
Zavalaga, C. B.; Plenge, M. A.; Bertolero, A. 2008a. The breeding biology of the Peruvian Tern (Sterna
lorata) in Peru. Waterbirds 31(4): 550-560.
Zavalaga, C. B.; Plenge, M. A.; Bertolero, A. 2008b. Nesting habitat and numbers of Peruvian Terns at five
breeding sites in the central-southern coast of Peru. Ornitologia Neotropical 19(4): 587-594.
Citation
BirdLife International. 2018. Sternula lorata. The IUCN Red List of Threatened Species 2018:
e.T22694685A132567771. http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22694685A132567771.en
Disclaimer
To make use of this information, please check the Terms of Use.
External Resources
For Images and External Links to Additional Information, please see the Red List website.
Appendix
Habitats
(http://www.iucnredlist.org/technical-documents/classification-schemes)
Major
Habitat Season Suitability
Importance?
8. Desert -> 8.1. Desert - Hot Breeding Suitable No
9. Marine Neritic -> 9.1. Marine Neritic - Pelagic Resident Marginal -
12. Marine Intertidal -> 12.2. Marine Intertidal - Sandy Shoreline and/or Breeding Suitable Yes
Beaches, Sand Bars, Spits, Etc
13. Marine Coastal/Supratidal -> 13.3. Marine Coastal/Supratidal - Coastal Breeding Suitable Yes
Sand Dunes
13. Marine Coastal/Supratidal -> 13.4. Marine Coastal/Supratidal - Coastal Breeding Suitable No
Brackish/Saline Lagoons/Marine Lakes
Threats
Threat Timing Scope Severity Impact Score
1. Residential & commercial development -> 1.1. Ongoing Majority (50- Slow, significant Medium
Housing & urban areas 90%) declines impact: 6
Stresses: 1. Ecosystem stresses -> 1.1. Ecosystem conversion

1. Ecosystem stresses -> 1.2. Ecosystem degradation
1. Residential & commercial development -> 1.2. Ongoing Minority (50%) Slow, significant Low impact: 5
Commercial & industrial areas declines

1. Residential & commercial development -> 1.3. Ongoing Majority (50- Slow, significant Medium
Tourism & recreation areas 90%) declines impact: 6

11. Climate change & severe weather -> 11.3. Ongoing Majority (50- Negligible declines Low impact: 5
Temperature extremes 90%)
Stresses: 2. Species Stresses -> 2.3. Indirect species effects ->

2.3.7. Reduced reproductive success
2. Agriculture & aquaculture -> 2.1. Annual & Ongoing Minority (50%) Slow, significant Low impact: 5
perennial non-timber crops -> 2.1.4. Scale declines
Unknown/Unrecorded
Stresses: 1. Ecosystem stresses -> 1.2. Ecosystem degradation
2. Agriculture & aquaculture -> 2.3. Livestock farming Ongoing Minority (50%) Slow, significant Low impact: 5
& ranching -> 2.3.3. Agro-industry grazing, ranching declines
or farming
3. Energy production & mining -> 3.1. Oil & gas Ongoing Minority (50%) Slow, significant Low impact: 5
drilling declines
5. Biological resource use -> 5.4. Fishing & harvesting Ongoing Majority (50- Slow, significant Medium
aquatic resources -> 5.4.3. Unintentional effects: 90%) declines impact: 6
(subsistence/small scale) [harvest]

Stresses: 2. Species Stresses -> 2.2. Species disturbance
2. Species Stresses -> 2.3. Indirect species effects ->
6. Human intrusions & disturbance -> 6.1. Ongoing Majority (50- Slow, significant Medium
Recreational activities 90%) declines impact: 6

7. Natural system modifications -> 7.2. Dams & water Ongoing Minority (50%) Slow, significant Low impact: 5
management/use -> 7.2.3. Abstraction of surface declines
water (agricultural use)

8. Invasive and other problematic species, genes & Ongoing Majority (50- Slow, significant Medium
diseases -> 8.1. Invasive non-native/alien 90%) declines impact: 6
species/diseases -> 8.1.2. Named species (Felis catus)

Stresses: 2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.2. Species disturbance
diseases -> 8.1. Invasive non-native/alien 90%) declines impact: 6
species/diseases -> 8.1.2. Named species (Canis

familiaris)
diseases -> 8.2. Problematic native species/diseases 90%) declines impact: 6
-> 8.2.2. Named species (Unspecified Lycalopex)

Stresses: 2. Species Stresses -> 2.1. Species mortality
2. Species Stresses -> 2.2. Species disturbance
Conservation Actions in Place


In-Place Research, Monitoring and Planning
Action Recovery plan: No
Systematic monitoring scheme: No
In-Place Land/Water Protection and Management
Conservation sites identified: Yes, over part of range
Occur in at least one PA: Yes
Invasive species control or prevention: No
In-Place Species Management
Successfully reintroduced or introduced beningly: No
Subject to ex-situ conservation: No
In-Place Education
Subject to recent education and awareness programmes: No
Included in international legislation: Yes
Subject to any international management/trade controls: No
Conservation Actions Needed

Conservation Actions Needed

1. Land/water protection -> 1.1. Site/area protection
3. Species management -> 3.2. Species recovery
5. Law & policy -> 5.1. Legislation -> 5.1.2. National level
5. Law & policy -> 5.3. Private sector standards & codes
Research Needed
Research Needed
1. Research -> 1.2. Population size, distribution & trends
Additional Data Fields

Distribution
Estimated area of occupancy (AOO) (km²): 21
Continuing decline in area of occupancy (AOO): Yes
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) (km²): 67600
Continuing decline in extent of occurrence (EOO): Unknown
Distribution
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 6-10
Continuing decline in number of locations: Yes
Extreme fluctuations in the number of locations: No
Population
Number of mature individuals: 600-1700
Continuing decline of mature individuals: Yes
Extreme fluctuations: No
Population severely fragmented: No
No. of subpopulations: 2-100
Continuing decline in subpopulations: Yes
Extreme fluctuations in subpopulations: No
All individuals in one subpopulation: No
No. of individuals in largest subpopulation: 1-89
Habitats and Ecology

Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 9
Movement patterns: Not a Migrant
Congregatory: Congregatory (and dispersive)
The IUCN Red List Partnership
The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species
Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership.
The IUCN Red List Partners are: Arizona State University; BirdLife International; Botanic Gardens
Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew;
Sapienza University of Rome; Texas A&M University; and Zoological Society of London.
THE IUCN RED LIST OF THREATENED SPECIES™

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The IUCN Red List of Threatened Species™

ISSN 2307-8235 (online)

Sternula lorata, Peruvian Tern

THE IUCN RED LIST OF THREATENED SPECIES™

Animalia Chordata Aves Charadriiformes Laridae

Taxon Name: Sternula lorata (Philippi & Landbeck, 1861)

Year Published: 2018

Date Assessed: August 7, 2018

Previously Published Red List Assessments

2012 – Endangered (EN)

2010 – Endangered (EN)

2008 – Endangered (EN)

2006 – Endangered (EN)

2005 – Endangered (EN)

2004 – Near Threatened (NT)

1994 – Lower Risk/least concern (LR/lc)

1988 – Lower Risk/least concern (LR/lc)

Habitat and Ecology (see Appendix for additional information)

Threats (see Appendix for additional information)

Conservation Actions (see Appendix for additional information)

8. Desert -> 8.1. Desert - Hot Breeding Suitable No

9. Marine Neritic -> 9.1. Marine Neritic - Pelagic Resident Marginal -

Threat Timing Scope Severity Impact Score

Stresses: 1. Ecosystem stresses -> 1.1. Ecosystem conversion

Stresses: 1. Ecosystem stresses -> 1.1. Ecosystem conversion

Stresses: 1. Ecosystem stresses -> 1.1. Ecosystem conversion

Stresses: 2. Species Stresses -> 2.3. Indirect species effects ->

Stresses: 1. Ecosystem stresses -> 1.2. Ecosystem degradation

(subsistence/small scale) [harvest]

Stresses: 2. Species Stresses -> 2.2. Species disturbance

water (agricultural use)

species/diseases -> 8.1.2. Named species (Felis catus)

species/diseases -> 8.1.2. Named species (Canis

-> 8.2.2. Named species (Unspecified Lycalopex)

Conservation Actions in Place

Conservation Actions in Place

Action Recovery plan: No

Systematic monitoring scheme: No

In-Place Land/Water Protection and Management

Occur in at least one PA: Yes

Invasive species control or prevention: No

In-Place Species Management

Successfully reintroduced or introduced beningly: No

Subject to ex-situ conservation: No

Subject to recent education and awareness programmes: No

Included in international legislation: Yes

Subject to any international management/trade controls: No

Conservation Actions Needed

Conservation Actions Needed

3. Species management -> 3.2. Species recovery

Additional Data Fields

Continuing decline in area of occupancy (AOO): Yes

Extreme fluctuations in area of occupancy (AOO): No

Estimated extent of occurrence (EOO) (km²): 67600

Continuing decline in extent of occurrence (EOO): Unknown

Number of Locations: 6-10

Continuing decline in number of locations: Yes

Extreme fluctuations in the number of locations: No

Continuing decline of mature individuals: Yes