Vireo bellii 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Vireonidae

Scientific Name: Vireo bellii
Species Authority: Audubon, 1844
Common Name(s):
English Bell's Vireo

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Butcher, G., Rosenberg, K. & Wells, J.
Facilitator/Compiler(s): Benstead, P., Bird, J., Harding, M., Sharpe, C J
This species has undergone moderately rapid declines and hence is considered to be Near Threatened.

Previously published Red List assessments:
2008 Near Threatened (NT)
2004 Near Threatened (NT)
2000 Lower Risk/least concern (LR/lc)
1994 Lower Risk/least concern (LR/lc)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: Vireo bellii summers in central and south-western USA and northern Mexico. Its winter range extends from south Baja California along the west coast of Central America, through Mexico, El Salvador, Guatemala, Nicaragua and Honduras (Brown 1993). The species has shown a decline of 2.7% per year since 1966 (J. Wells and K. Rosenberg in litt. 2003).

Countries occurrence:
El Salvador; Guatemala; Honduras; Mexico; Nicaragua; United States
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 291000
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 2000
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Rich et al. (2004).

Trend Justification:  This species has undergone a large and statistically significant decrease over the last 40 years in North America (-66.1% decline over 40 years, equating to a -23.7% decline per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).
Current Population Trend: Decreasing
Additional data:
Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and Ecology: It frequents dense, low, shrubby vegetation in its breeding range where it has been extensively studied (Brown 1993). However, very little is known about its density, ecology or habitat use in the winter grounds.

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 4.1
Movement patterns: Full Migrant

Threats [top]

Major Threat(s): Habitat loss and modifications through agricultural spread, logging and housing developments have caused declines and continue to threaten the species. Secondarily, rates of brood parasitism by Brown-headed Cowbirds (Molothrus ater), have caused reductions in breeding populations in south-west USA (Brown 1993).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Trapping cowbirds can significantly reduce brood parasitism (Collins et al. 1991), and is a standard management tool in one California study area (Beezley and Rieger 1987).

Conservation Actions Proposed
Protect key habitats for the species and manage others in a beneficial way. Continue to monitor trends and ascertain whether it is still declining. Identify the key threats and develop appropriate actions to tackle them.

Citation: BirdLife International. 2012. Vireo bellii. The IUCN Red List of Threatened Species 2012: e.T22705156A38237079. . Downloaded on 25 November 2015.
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