LC
Snowy-crowned Tern Sterna trudeaui



Taxonomy

Taxonomic source(s)
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 Least Concern
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency Does not normally occur in forest
Land mass type Average mass 153 g
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 2,770,000 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 670-6700 poor estimated 2009
Population trend Stable 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) 11 - - -

Population justification: The population is estimated to number 1,000-10,000 individuals, roughly equating to 670-6,700 mature individuals.

Trend justification: The overall population trend is stable, although some populations have unknown trends (Delany and Scott 2006).


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Argentina N Extant Yes
Brazil N Extant Yes
Chile N Extant Yes
Falkland Islands (Malvinas) V Extant
Paraguay V Extant
Uruguay N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable non-breeding
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes suitable breeding
Marine Coastal/Supratidal Coastal Freshwater Lakes suitable non-breeding
Marine Coastal/Supratidal Coastal Freshwater Lakes suitable breeding
Marine Intertidal Salt Marshes (Emergent Grasses) suitable non-breeding
Marine Intertidal Salt Marshes (Emergent Grasses) suitable breeding
Marine Neritic Macroalgal/Kelp suitable non-breeding
Marine Neritic Macroalgal/Kelp suitable breeding
Marine Neritic Pelagic suitable non-breeding
Marine Neritic Pelagic suitable breeding
Marine Neritic Seagrass (Submerged) suitable non-breeding
Marine Neritic Seagrass (Submerged) suitable breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable non-breeding
Marine Neritic Subtidal Loose Rock/pebble/gravel suitable breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable non-breeding
Marine Neritic Subtidal Rock and Rocky Reefs suitable breeding
Marine Neritic Subtidal Sandy suitable non-breeding
Marine Neritic Subtidal Sandy suitable breeding
Marine Neritic Subtidal Sandy-Mud suitable non-breeding
Marine Neritic Subtidal Sandy-Mud suitable breeding
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands major breeding
Wetlands (inland) Permanent Saline, Brackish or Alkaline Lakes suitable non-breeding
Wetlands (inland) Permanent Saline, Brackish or Alkaline Lakes suitable breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Natural system modifications Dams & water management/use - Abstraction of surface water (agricultural use) Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Reduced reproductive success

Recommended citation
BirdLife International (2020) Species factsheet: Sterna trudeaui. Downloaded from http://www.birdlife.org on 16/07/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/07/2020.