|Scientific Name:||Vireo atricapilla|
|Species Authority:||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 Notes:||Gender agreement of species name follows David and Gosselin (2002a).|
|Red List Category & Criteria:||Vulnerable A2bce+3bce+4bce;C1+2a(i) 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.|
|Facilitator/Compiler(s):||Bird, J., Harding, M., Isherwood, I., Pople, R., Sharpe, C J, Wege, D., Derhé, M.|
This species qualifies as Vulnerable owing to rapid population declines throughout most of its contracting range. The population is already small and fragmented, but the disappearance of isolated populations and remaining breeding habitat indicate that these rapid declines will continue.
|Range Description:||Vireo atricapilla once bred from Kansas through Oklahoma to south-west Texas, USA, into central Coahuila and southern Nuevo Leon, Mexico, wintering along the Pacific coast of western Mexico from southern Sonora (Río Yaqui, Alvaro Obregón Dam) 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, Rivera et al. 2011). The species's distribution in Texas was assessed on private and public land in 57 counties across the state and found 13% of 10,700 point survey locations were occupied (McFarland et al. 2012). The species was found to be more common in the western part of the state (McFarland et al. 2012). In Oklahoma it is now restricted to a few sites in the Witchita Mountains where breeding habitat is fragmented (Grzybowski 1995). The total wintering area has been calculated to be 141,000 km2 (Rivera et al. 2011).|
Native:Mexico; United States
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population is estimated to number 8,000 individuals, equating to 5,300 mature individuals, having declined to c.6,000-10,000 by 2003. However, numbers for south-west Texas and Mexico are uncertain (J. Lyons in litt. 1999). The decline is not uniform: numbers are stable in the southern 25-30% of the historic breeding range, and management has arrested declines elsewhere (J. A. Grzybowski in litt. 1999).|
|Habitat and Ecology:||
It nests in low, very dense deciduous shrubland maintained by disturbances, such as fire, and in forest-grassland ecotone in Oklahoma, northern, and central Texas (Grzybowski 1995). Oaks Quercus spp. and densely foliaged shrubs (such as Dyosporus 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. 2012). In Mexico, it breeds at elevations of 1,000-2,000 m (Howell and Webb 1995). It winters from the lowlands up to 1,600 m (Howell and Webb 1995), often in arid deciduous scrub and bushy thickets associated with various woodland-types (S. N. G. Howell in litt. 1998). Wintering density in Sinaloa has been calculated to be 7.68 individuals per km2 (González-Medina et al. 2009).
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 are as high as 50% in some locations; primarily from snakes, fire ants Solenopsis spp. and mammals (Stake and Cimprich 2003, Campomizzi et al. 2009). 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 (Rivera et al. 2011).
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 USA.
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. 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. 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 2012. Vireo atricapilla. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 02 September 2015.|
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