NT
Elegant Tern Thalasseus elegans



Taxonomy

Taxonomic note
Thalasseus elegans (del Hoyo and Collar 2014) was previously placed in the genus Sterna.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
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.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm#.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2018 Near Threatened D2
2016 Near Threatened D2
2012 Near Threatened D2
2010 Near Threatened D2
2008 Near Threatened D2
2006 Near Threatened
2004 Near Threatened
2000 Lower Risk/Near Threatened
1994 Lower Risk/Near Threatened
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency Does not normally occur in forest
Land mass type Land-mass type - continent
Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 240,000 medium
Extent of Occurrence non-breeding (km2) 11,400,000 medium
Extent of Occurrence breeding/resident (km2) 1,300 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals medium estimated 2002
Population trend Stable poor suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 10.9 - - -

Population justification: The estimated population is 51,000-90,000 individuals (Kushlan et al. 2002) with up to 95% breeding on Isla Rasa in the Gulf of California (Velarde and Anderson 1994). At least three other Mexican islands are used at least occasionally (Velarde and Anderson 1994). In addition, small populations breed on Bolsa Chica (50-4,000 pairs, first recorded in 1987) and in San Diego bay (500-800 pairs) (Velarde and Anderson 1994, Gochfeld and Burger 1996, E. Verlarde in litt. 1998, B. Tershy and B. Keitt in litt. 1999).

Trend justification: The population is suspected to undergo dramatic fluctuations in response to El Niño Southern Oscillation events and subsequent fluctuations in fish populations (Velarde and Anderson 1994, B. Tershy and B. Keitt in litt. 1999).


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Belgium V Extant
Chile N Extant Yes
Colombia N Extant Yes
Costa Rica N Extant Yes
Denmark V Extant
Ecuador N Extant Yes
El Salvador N Extant Yes
Falkland Islands (Malvinas) V Extant
France V Extant
Guatemala U Extant Yes
Honduras U Extant
Ireland V Extant
Mexico N Extant Yes
Nicaragua N Extant Yes
Panama N Extant Yes
Peru N Extant
United States Minor Outlying Islands (to USA) V Extant
USA N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Chile Bahía de Mejillones
Chile Costa sur de Arica
Chile Desembocadura del río Chauhuín
Chile Desembocadura del Río Itata
Chile Desembocadura del Río Lluta
Chile Desembocadura del Río Maipo
Chile Estero Mantagua y Desembocadura del Río Aconcagua
Chile Humedal de Arauco
Chile Humedal-Estuario Tubul-Raqui
Chile Humedal-Marisma Rocuant Andalién
Chile Lago Budi
Chile Muelle Casa del Soldado
Chile Paradero de aves Roquerios de Laucho y Lisera
Chile Patranca Island
Chile Playa las Machas
Chile Playa sector Chacalluta
Chile Playa Sur de Arica
Chile Puerto de Arica
Chile Punta Huezhui
Ecuador Lagunas de Ecuasal-Salinas
Mexico Estero Cardonal
Mexico Estero Santa Cruz
Mexico Isla Alcatraz
Mexico Isla Rasa
Mexico Istmo de Tehuantepec-Mar Muerto
Peru Laguna de Ite
Peru Reserva Nacional de Paracas
USA Bolsa Chica
USA Orange Coast Wetlands
USA Palos Verdes
USA Pier 400 Tern Colony (formerly Terminal Island)
USA San Diego Bay - South

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes major non-breeding
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes major breeding
Marine Intertidal Mud Flats and Salt Flats suitable passage
Marine Intertidal Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major non-breeding
Marine Intertidal Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc major breeding
Marine Neritic Macroalgal/Kelp major non-breeding
Marine Neritic Macroalgal/Kelp major breeding
Marine Neritic Seagrass (Submerged) major non-breeding
Marine Neritic Seagrass (Submerged) major breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel major breeding
Marine Neritic Subtidal Rock and Rocky Reefs major non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs major breeding
Marine Neritic Subtidal Sandy major non-breeding
Marine Neritic Subtidal Sandy major breeding
Marine Neritic Subtidal Sandy-Mud major non-breeding
Marine Neritic Subtidal Sandy-Mud major breeding
Altitude 0 - 100 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Causing/Could cause fluctuations Medium Impact: 6
Stresses
Indirect ecosystem effects, Reduced reproductive success
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Unknown Past Impact
Stresses
Reduced reproductive success, Species mortality
Climate change & severe weather Temperature extremes Timing Scope Severity Impact
Ongoing Majority (50-90%) Causing/Could cause fluctuations Medium Impact: 6
Stresses
Indirect ecosystem effects, Reduced reproductive success
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Named species Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Rapid Declines Past Impact
Stresses
Indirect ecosystem effects, Species disturbance, Reduced reproductive success

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food (human) Whole Adults and juveniles Wild Non-trivial Recent
Food - human - - Non-trivial Recent

Recommended citation
BirdLife International (2019) Species factsheet: Thalasseus elegans. Downloaded from http://www.birdlife.org on 19/04/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/04/2019.