Vireo masteri 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Vireonidae

Scientific Name: Vireo masteri
Species Authority: Salaman & Stiles, 1996
Common Name(s):
English Choco Vireo, Chocó Vireo
Vireo sp. nov. — Collar et al. (1994)
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.
Identification information: 10 cm. Small, olive-and-yellow, warbler-like bird. Olive-green above with broad, prominent yellow supercilium contrasting with greyish-olive crown and dark eye-stripe. Dark brown remiges with olive-green edges. Broad, creamy, double wing-bar. Creamy-white below, with yellow breast, flanks and vent. Blackish maxilla, pale mandible. Bright bluish legs. Similar spp. Brown-capped Vireo V. leucophrys has brown upperparts and lacks wing-bars. Rufous-rumped Antwren Terenura callinota has rufous rump and longer tail. Voice Variable, high-pitched, warbling song 6-20 notes over 1-3 seconds. Contact call brief dry chip, and disturbance note a nasal zhree-zhree-zhree, most similar to Red-eyed Vireo Vireo olivaceus in quality.

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(i,ii,iii,v) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Jahn, O., Salaman, P., Strewe, R., Valenzuela, P. & Brinkhuizen, D.
Facilitator/Compiler(s): Benstead, P., Gilroy, J., O'Brien, A. & Sharpe, C J
This species has a small population, a small range and is known with certainty from just three separate areas. Its range and population are likely to be declining because of continuing habitat destruction. Recent searches in suitable habitat in intermediate areas have failed to find this species, and it is therefore classified as Endangered.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Vireo masteri is restricted to the Pacific slope of the West Andes of Colombia and north-western Ecuador. It is known from half a dozen locations in Colombia (Alto de Pisones and Montezuma, Risaralda, and two in the Junín area, Nariño [Salaman 1994, Salaman and Stiles 1996, Salaman in litt. 1999, 2000, 2003, Freeman et al. 2012]), and Ecuador (Alto Tambo [Jahn et al. 2007] and El Cristal, Esmeraldas, and the Mashpi road, Pichincha [D. Brinkhuizen in litt. 2010, Brinkhuizen and Solano-Ugalde 2012]). 

Countries occurrence:
Colombia; Ecuador (Ecuador (mainland))
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:3100
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:3Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):1100
Upper elevation limit (metres):1600
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: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, and although the species may occur in appropriate habitat in between these sites (Salaman and Stiles 1996, Salaman in litt. 1999, 2000, 2003, Renjifo et al. 2002), searches of the intervening area have completely failed to find the species, despite excellent knowledge of its vocalizations and its reliable response to playback (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 rate of habitat loss within occupied cloud-forest habitat types is unknown, but the species is suspected to be declining at a slow rate.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:15423-15777Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:2-100Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:In Colombia, it has only been recorded in wet (>5,000 mm per year) primary cloud-forest, usually on steeply sloping terrain with a rather broken canopy and natural tree-fall gaps (Salaman and Stiles 1996, Renjifo et al. 2002). Areas with abundant palms, epiphytes, ferns and moss between 1,100 and 1,600 m are favoured (Salaman and Stiles 1996, Salaman in litt. 1999, 2000, 2003). In Ecuador, the species has been found in a wider range of habitats, including wet primary forest on level ground and steep slopes, as well as forest edges bordering pastures, roads, and railways, and re-growth of intensively logged forest, between 800 and 1,500m (Jahn et al. 2007). In Colombia, up to five territorial singing males were encountered per kilometre of transect (Salaman in litt. 1999, 2000, 2003), whilst densities of 15.9 ±1.4 territories/km2 were estimated within suitable habitat in Ecuador (Jahn et al. 2007). Encountered in pairs, individuals and family parties, it primarily forages in the canopy, or occasionally lower down in clearings and tree-falls. It is often found accompanying mixed-species flocks (Salaman and Stiles 1996, Salaman in litt. 1999, 2000, 2003, Jahn et al. 2007). Breeding takes place during the dry season, from June to October, and adults have been seen feeding juveniles in August (Salaman and Stiles 1996). It is a very active forager, feeding on invertebrates (Salaman and Stiles 1996).

Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):4.2
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): The Chocó region has long been a source of timber, but logging has intensified since the mid-1970s. Plans to colonise and develop the region are progressing through infrastructural improvement, particularly the rapid expansion of the road network, and are increasing the impact of logging, small-scale agriculture and gold mining (Salaman 1994, Wege and Long 1995, Salaman and Stiles 1996). Coca cultivation is a growing problem at lower altitudes (Salaman in litt. 1999, 2000, 2003). In Colombia, Río Ñambi Community Nature Reserve is threatened by logging, and disputes over land ownership, but the population is currently secure (Salaman in litt. 1999, 2000, 2003). Alto de Pisones remains unprotected and largely deforested (Salaman in litt. 1999, 2000, 2003). In Ecuador, the species is presumed to occur within the Cotacachi-Cayapas Ecological Reserve (243,638 ha; altitudinal range 80-4,900 m), Esmeraldas. However, the reserve is threatened by incursions from local communities, as well as colonists from Colombia and other regions of Ecuador (Jahn et al. 2007, Jahn in litt. 2007). Forests around Alto Tambo are largely unprotected and threatened by clearance for cattle ranching and forestry projects (Jahn et al. 2007, Jahn in litt. 2007).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
In Colombia, it is protected in the Tatamá National Park (Freeman et al. 2012), Las Tangaras Nature Reserve, Chocó and El Pangan and Río Ñambí Community Nature Reserves, Nariño (Salaman and Stiles 1996, Strewe in litt. 1999, Salaman in litt. 1999, 2000, 2003, 2012). Although the population at Alto Pisones remains unprotected, the area may be included in the proposed Caramanta National Park, a management plan for which is in preparation (Stiles 1998). In Ecuador, populations may exist within the Cotacachi-Cayapas Ecological Reserve (Jahn et al. 2007). Some of the occupied area at Alto Tambo is protected as an extractive reserve by Fundación para el Desarrollo Forestal, indicating that the suitability of the area for this species may depend on future forestry practices (intensive vs. selective harvesting schemes; natural-forest management vs. plantations of exotic timber tree species) (Jahn et al. 2007).

Conservation Actions Proposed
Survey the montane forests between the known locations in both Colombia and Ecuador. Surveys should aim to determine presence and population densities across the region, with emphasis on existing reserves, e.g. Cotacachi-Cayapas Ecological Reserve. Protect the population at Alto de Pisones effectively and enforce protection of Río Ñambi Community Nature Reserve (Salaman in litt. 1999, 2000, 2003). Ensure future protection of Cotacachi-Cayapas Ecological Reserve (Jahn et al. 2007). Encourage sympathetic management of extractive forest reserves close to Alto Tambo, owned by Fundación para el Desarrollo Forestal (Jahn et al. 2007).

Citation: BirdLife International. 2016. Vireo masteri. The IUCN Red List of Threatened Species 2016: e.T22705146A94002654. . Downloaded on 21 January 2017.
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