|Scientific Name:||Vireo atricapilla Woodhouse, 1852|
Vireo atricapillus atricapillus Stotz et al. (1996)
Vireo atricapillus atricapillus Sibley and Monroe (1990, 1993)
Vireo atricapillus atricapillus BirdLife International (2000)
Vireo atricapillus atricapillus Collar and Andrew (1988)
Vireo atricapillus atricapillus 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:||12 cm. Well-marked and distinctive vireo. Male has black head, white lores and eye-ring (giving spectacled appearance), olive upperparts, blackish wings fringed olive and two yellowish wing-bars. Whitish underparts with olive flanks. Red iris. Female duller and with grey head. Juvenile browner. Similar spp. Cassin's Vireo V. cassinii differs from female in larger size and bill, and lacks red iris. Voice Song a series of rapid 2-3 note phrases. Call a dry chit-it.|
|Red List Category & Criteria:||Vulnerable A2bce+3bce+4bce ver 3.1|
|Reviewer(s):||Butchart, S. & Symes, A.|
|Contributor(s):||Grzybowski, J., Howell, S., Lockwood, M., Lyons, J., Wauer, R., Campomizzi, A.J., González-Medina, E., McFarland, T., Colón, M., González Rojas, J.I., MacGregor-Fors, I. & Contreras Balderas, A.J.|
|Facilitator/Compiler(s):||Bird, J., Harding, M., Isherwood, I., Pople, R., Sharpe, C.J., Wege, D., Derhé, M., Ashpole, J|
This species qualifies as Vulnerable owing to rapid population declines throughout most of its contracting range.
|Previously published Red List assessments:|
|Range Description:||This species once bred from Kansas through Oklahoma to south-west Texas, USA, into central Coahuila, north-western and southern Nuevo Leon and south-western Tamaulipas (Contreras-Balderas et al. 2012, González-Rojas et al. 2014, J. I. González Rojas in litt. 2016), Mexico, wintering along the Pacific coast of western Mexico from Sinaloa to Oaxaca (Salina Cruz on the Pacific coast and Matias Romero, and inland) (Grzybowski 1995, Howell and Webb 1995, S. N. G. Howell in litt. 1998, Vega Rivera et al. 2011, Colón et al. 2015). Winter records from Sonora are likely to be of individuals on migration (Powell 2013). There is no known habitat in Kansas (T. McFarland in litt. 2016), whilst in Oklahoma it is now restricted to a relatively small number of sites in the Witchita Mountains where breeding habitat is fragmented (Grzybowski 1995). Based on a state-wide survey of vireos in Texas, the species is known to occur in 57 counties across the state with 13% of 10,700 point survey locations occupied (McFarland et al. 2012). The species was found to be more common in the western part of the state (McFarland et al. 2012). Less is known about the wintering range, which has been estimated to cover 141,000 km2 (Vega Rivera et al. 2011).|
Native:Mexico; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population size is difficult to determine. In 2006 the total population was estimated to be 6,010 males in the U.S. and 259 males in Mexico (Wilkins et al. 2006). Equivalent to c.12,020 mature individuals or 18,030 individuals in the USA and 518 mature individuals or 777 individuals in Mexico. Altogether these figures estimate a global population of c.12,500 mature individuals or 18,800 individuals. However, these numbers for the U.S. mostly accounted for vireos detected on public property and much more breeding habitat may be located on private lands (McFarland et al. 2012).|
Benson and Benson (1990) estimated 6,301 ± 3,162 pairs in northern Coahuila, Mexico. In 2012 and 2013, Morrison et al. (2014) found a total of 341 vireos in three states in Mexico.
Partners in Flight (2013) estimate the global population to be 20,000 individuals. This is equivalent to c. 13,300 mature individuals.
Trend Justification: A rapid and on-going population decline is estimated to be occurring, based on survey results (J. Lyons in litt. 1999). However it is not clear whether the species is continuing to decrease (T. McFarland in litt. 2016). A declining population trend is precautionarily retained here.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||It nests in low, very dense deciduous shrubland maintained by disturbances, such as fire, in forest-grassland ecotone, and in deciduous and oak-juniper woodlands in Oklahoma, northern, and central Texas (Grzybowski 1995, Pope et al. 2013). Oaks Quercus spp. and densely foliaged shrubs (such as Diospyros texana, Rhus virens and Sophora segundiflora [M. Lockwood in litt. 1999]) frequently occur in the species's habitat. In west Texas, it occurs in xeric thornscrub vegetation (Smith et al. 2012a). In Mexico, it breeds in chaparral and submontane thornscrub at elevations of 920-2,000 m (Howell and Webb 1995, González-Rojas et al. 2014, J. I. González-Rojas in litt. 2016). It has also been recorded during the breeding season near the city of Monterrey in Nuevo León which suggests that it may be found in suitable habitat patches within urban areas (Contreras-Balderas et al. 2012). In central Texas, juveniles were found to show a preference for riparian vegetation (Dittmar 2014). Little is known of the species's migration routes however it has been observed in open and secondary forests and may migrate through the Sierra Madre Oriental and the Transvolcanic Mexican Belt although further research is needed to confirm this (MacGregor-Fors et al. 2012, I. MacGregor-Fors in litt. 2016). It typically winters in tropical dry forests and pine-oak forests from the lowlands up to 1,600 m (Howell and Webb 1995, Colón et al. 2015). Wintering density in Sinaloa has been calculated to be 7.68 individuals per km2 with the species preferring tropical deciduous forest associated with rivers and streams (Gonzalez-Medina et al. 2009).|
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||4.2|
|Movement patterns:||Full Migrant|
Fire suppression is probably the most serious threat, but urban development and agricultural conversion (especially to pasture) have caused significant habitat loss in Oklahoma, northern and central Texas (Grzybowski 1995, J. Lyons in litt. 1999). Intensive grazing by livestock and native grazers has further degraded habitat (Grzybowski 1995). The wintering habitat has been modified by changes in land use by reducing the potential suitable area or causing habitat fragmentation and reduced quality of winter habitat (González-Medina et al. 2009). Brown-headed Cowbirds Molothrus ater inflict high rates of brood-parasitism, as high as 100% of nests, in some locations (Grzybowski 1995, Farrell 2011). Rates of nest predation as high as 50% in some locations have been reported; primarily from snakes, fire ants Solenopsis spp. and mammals (Stake and Cimprich 2003, Campomizzi et al. 2009). Snakes and birds are reported to be the primary predators of this species, with mammals, ants and katydids also found to predate the species (Stake and Cimprich 2003, Campomizzi et al. 2009, Conkling et al. 2012, Smith et al. 2012b). Frequency of parasitism and nest predation have been documented in <50% of locations in west Texas where the most common nest predators were Brown-headed Cowbirds, snakes, and greater roadrunners (Geococcyx californianus [Smith et al. 2012]). The high return rates of birds to breeding territories suggests few threats on the wintering grounds (Grzybowski 1995). However, only 7.1% of its predicted wintering area is protected (Vega Rivera et al. 2011) and tropical dry forests in Mexico are regularly cleared for agriculture and grazing (Miles et al. 2006). Although little is known of the species's migration routes, it may use forested areas thus deforestation in such areas could have a negative impact on the species (I. MacGregor-Fors in litt. 2016).
Conservation Actions Underway
Conservation actions are occurring on public and private land. Management programs to restore vegetation and manage cowbirds have occurred at various locations including Balcones Canyonlands National Wildlife Refuge (Sexton 1997), Fort Hood (Kostecke et al. 2005), Ker Wildlife Management Area, and Wichita Mountains (Grzybowski 1995). On private land, conservation has occurred through various programs including Habitat Conservation Plans, Texas Parks and Wildlife Department’s Wildlife Management Plans, the Landowner Incentive Program, and the Leon River Restoration Project. Research is ongoing on breeding and wintering areas in Mexico and the USA. Modelling work on the species's migration is ongoing (I. MacGregor-Fors in litt. 2016). The species is included on the 'Watch List' of the State of North America's Birds as a species of high conservation concern (NABCI 2016).
Conservation Actions Proposed
Monitor the status and trends in occupancy, abundance, or both to determine abundance and trend. Clarify the distribution in Mexico and estimate breeding numbers. Continue to study the species's migration routes (MacGregor-Fors et al. 2012) and identify important stopover sites (I. MacGregor-Fors in litt. 2016). Research the species's ability to adapt to habitat changes and urban environments (A. J. Contreras Balderas in litt. 2016). Investigate dispersal and survival of juveniles during migration and on wintering grounds (Dittmar 2014). Develop conservation actions through engagement with private landowners to balance conservation actions with other land uses. Assess threats on wintering grounds (J. Lyons in litt. 1999). Coordinate a range-wide action plan (J. A. Grzybowski in litt. 1999). Restore suitable habitat within its breeding range, including managing areas to promote dense deciduous cover for nesting (Bailey and Thompson 2007) and protect riparian vegetation (Dittmar 2014). Continue to manage cowbird populations as research suggests that recovery of the species relies on such management (Campomizzi et al. 2013, Wilsey et al. 2013, T. McFarland in litt. 2016). Locate and protect wintering habitats, focusing primarily on sites linked to rivers and streams /or fresh water resources in tropical dry forest. Establish a monitoring program for the wintering population in key areas.
|Citation:||BirdLife International. 2016. Vireo atricapilla. The IUCN Red List of Threatened Species 2016: e.T22705159A94003467.Downloaded on 19 October 2017.|
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