• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

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.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2019	Near Threatened	B2b(i,ii,iii)
2016	Endangered	B1ab(i,ii,iii,v)
2012	Endangered	B1ab(i,ii,iii,v)
2008	Endangered	B1a+b(i,ii,iii,v)
2004	Endangered
2000	Endangered
1994	Vulnerable
1988	Not Recognised

Migratory status	not a migrant	Forest dependency	high
Land-mass type	continent	Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	34,500 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	14200-17000 mature individuals	poor	estimated	2007
Population trend	decreasing	poor	inferred	1998-2008
Rate of change over the past 10 years/3 generations (longer of the two periods)	10-19%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	10-19%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	10-19%	-	-	-
Generation length	4.2 years	-	-	-
Number of subpopulations	2-100	-	-	-

Population justification: Its potential global population was estimated to be as high as 78,000 ±7,000 mature individuals based on estimates of the area of forest cover within its range. However, the two occupied areas in Colombia are 520 km apart. Although the species may occur in appropriate habitat in between these sites (Salaman and Stiles 1996, P. Salaman in litt. 1999, 2000, Renjifo et al. 2002, P. Salaman in litt. 2003), searches of the intervening area have completely failed to find the species, despite excellent knowledge of its vocalizations and its reliable response to playback (P. Salaman in litt. 1999, 2000, 2003). Therefore, a precautionary population size estimate was made of 15,600 ±1,400 mature individuals based upon a figure of 20% occupancy within the Extent of Occurrence (Jahn et al. 2007). The total population is estimated to number 20,000-25,000 individuals, based on population density data from Ecuador extrapolated over the species's known range. Population size is thought to be declining owing to loss and fragmentation of its habitat.

Trend justification: The species is thought to be in decline, but the rate of decline has not been assessed directly. A recent analysis of the deforestation rate in the Chocó area of northwestern Ecuador found that on average, 61% of the original forest cover has been lost (Finer and Mamani 2019, M. Schaefer in litt. 2019). Forest loss has been most severe in the lowlands, with 68% of the original forest cover gone. In mid and upper elevations, where Chocó Vireo is found, about 50% of the original forest cover has disappeared (Finer and Mamani 2019, M. Schaefer in litt. 2019). Between 2000 and 2018, deforestation rates in the Ecuadorian Chocó amounted to 20% (Finer and Mamani 2019, M. Schaefer in litt. 2019). There are no detailed data available for the rate of forest loss in the Colombian part of the range. While forest cover in western Colombia was stable overall, or even increasing between 2001 and 2010 (Sanchez-Cuervo and Aide 2013), it is feared that deforestation rates have increased since (M. Schaefer in litt. 2019). Therefore precautionarily, it is assumed that the overall forest cover throughout the range has declined by 20% between 2000 and 2018. Assuming furthermore that deforestation continues at the same rate and that the population decline is proportional to the deforestation rate, it is suspected that Choco Vireo is declining at 14.5% over three generations (12.6 years). To account for local differences in the rate of population decline, it is here placed in the band 10-19% over three generations.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Colombia	extant	native	yes
Ecuador	extant	native	yes

Country/Territory	IBA Name
Colombia	Alto de Pisones
Colombia	Reserva Natural El Pangán
Colombia	Reserva Natural Río Ñambí
Ecuador	Mashpi-Pachijal

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	800 - 1600 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Livestock farming & ranching - Small-holder grazing, ranching or farming	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation
Energy production & mining	Mining & quarrying	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Housing & urban areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Choco Vireo Vireo masteri. Downloaded from https://datazone.birdlife.org/species/factsheet/choco-vireo-vireo-masteri on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/12/2024.