LC
Bell's Vireo Vireo bellii



Taxonomy

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

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

Red List history
Year Category Criteria
2021 Least Concern
2018 Least Concern
2016 Near Threatened A2bc+3bc+4bc
2012 Near Threatened A2bc+3bc+4bc
2008 Near Threatened A2b,c; A3b,c; A4b,c
2004 Near Threatened
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency low
Land-mass type continent
Average mass 8 g
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 4,930,000 km2 medium
Extent of Occurrence (non-breeding) 1,380,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 5700000 mature individuals medium inferred 2019
Population trend increasing medium inferred 1998-2008
Rate of change over the past 10 years/3 generations (longer of the two periods) 11% - - -
Generation length 2.34 years - - -

Population justification: The global population is inferred to number 5,700,000 mature individuals (Partners in Flight 2019). The California subspecies now numbers approximately 3,000 territorial males (Kus et al. 2010).

Trend justification: The species has been increasing at an average rate of 1.1% per year between 1970 and 2017 (Partners in Flight 2019). Assuming that the increase continues at the same rate, this would equate to an increase of 12% over the past ten years. The population in North America is increasing rapidly at a rate of 29% over the past ten years (Pardieck et al. 2018).


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
El Salvador extant native yes
Guatemala extant native yes yes
Honduras extant native yes
Mexico extant native yes yes yes yes
Nicaragua extant native yes
USA extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Vallecitos de Zaragoza
Mexico Nacimiento Río Sabinas-Sureste de la Sierra de Santa Rosa
Mexico Presa Cajón de Peñas
Mexico Presa el Tulillo
Mexico Presa Venustiano Carranza
Mexico Sierra Maderas del Carmen
USA Lynnville-Squaw Creek Mine Complex
USA Camp Pendleton
USA San Diego NWR Otay-Sweetwater Unit
USA San Luis Rey River
USA San Pasqual Valley - Lake Hodges
USA Santa Ana River Valley
USA Santa Clara River Valley
USA Anza-Borrego Riparian
USA Fort Chaffee
USA San Pedro Riparian National Conservation Area
USA Bill Williams River National Wildlife Refuge
USA Lower San Pedro River

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland suitable non-breeding
Forest Temperate major breeding
Shrubland Subtropical/Tropical Dry major non-breeding
Shrubland Subtropical/Tropical Dry major breeding
Shrubland Subtropical/Tropical High Altitude suitable non-breeding
Shrubland Subtropical/Tropical High Altitude suitable breeding
Shrubland Subtropical/Tropical Moist suitable non-breeding
Shrubland Subtropical/Tropical Moist suitable breeding
Shrubland Temperate suitable breeding
Altitude 0 - 2000 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Scale Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Unknown Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Unknown Unknown Unknown
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Problematic native species/diseases Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Natural system modifications Dams & water management/use - Dams (size unknown) Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion
Pollution Agricultural & forestry effluents - Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Unknown Unknown Unknown
Stresses
Ecosystem degradation
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Ongoing Unknown Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2023) Species factsheet: Vireo bellii. Downloaded from http://datazone.birdlife.org/species/factsheet/bells-vireo-vireo-bellii on 11/12/2023.
Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 11/12/2023.