Virginia’s Warbler was named for the spouse of Dr. W.W. Anderson who collected the first specimen in New Mexico in 1858. Adult males in breeding plumage are distinguished from other plain-winged Vermivora species by their bright yellow upper breast and undertail coverts, white belly and eye-ring, greenish yellow rump and uppertail coverts and rufous crown patch, often concealed. While Virginia’s Warbler was considered conspecific with Nashville Warbler (V. ruficapilla) by some authors (Phillips et al. 1964), work by Johnson and coworkers (Brush and Johnson 1976, Johnson 1976) indicated they are separate species although closely related (Am. Ornithol. Union 1998).
DISTRIBUTION. During the 1987-1992 field work for the TBBA project, observers found 6 probable and 1 possible breeding occurrences in latilong 31104, quad H-7 in the Guadalupe Mountains and 2 probable and 1 possible in 30104-F1 in the Davis Mountains. Breeding by this warbler has been reported in both these ranges for Virginia’s Warbler (Oberholser 1974, Lockwood and Freeman 2004).
In other parts of the United States, this warbler breeds primarily in Nevada, Utah, Colorado, Arizona and New Mexico with additional populations in Idaho, Wyoming, South Dakota and California. The species winters in south- west Mexico in Nayarit, Jalisco, Colima, Michoacan, Guerrero and Oaxaca (Howell and Webb 1995, Olson and Martin 1999, Sauer et al. 2005).
SEASONAL OCCURRENCE. Migrating Virginia’s Warblers arrive in Texas from April 8 to June 16 with most arriving by mid-May. Southbound migrants have been recorded between August 21 and September 24 (Oberholser 1974, Lockwood and Freeman 2004). In Arizona atlasers found breeding evidence from May 1 through July 31 with most breeding observations in June and July (Wise-Gervais 2005). In Colorado some nesting activity continued into August (Melcher 1998).
BREEDING HABITAT. In Texas the breeding habitat of Virginia’s Warbler is mostly scrub oak thickets at about 2000 m (6600 ft) elevation (Oberholser 1974). In Colorado about 30% of breeding was found in scrub oak, 17-18% each in pinyon-juniper and non-oak montane shrub and 12% in upland riparian vegetation (Melcher 1998).
In Arizona almost half of breeding activity was found in 3 habitats, ponderosa pine-Gambel’s oak, ponderosa pine-Douglas fir and montane riparian, in almost equal numbers. Breeding was also observed in other habitats containing pine (Wise-Gervais 2005).
The nest is built on the ground, either under deciduous shrubs or in grass clumps, often on a slope, usually concealed from above. The female builds a base of coarse dead plant material and grass. A cup is built of interwoven strips of bark, grass stems, roots and moss. The nest is lined with similar materials. The outside diameter averages about 92 mm (3.7 in), height 53 mm (2.1 in), inside diameter 55 mm (2,2 in) and cup depth 36 mm (1.4 in).(Harrison 1979 , Olson and Martin 1999)
The female usually lays 3-6 smooth off-white to cream eggs with reddish-brown markings often in a wreath around the larger end. Incubation by the female lasts 11-14 days and the young birds leave the nest 10-14 days after hatching and remain dependent on their parents for food for at least 2 weeks. Only one brood is raised per season. Parasitism by Brown-headed Cowbirds (Molothrus ater) may be as high as 50% (Olson and Martin 1999).
STATUS. Virginia’s Warbler is a rare to uncommon summer resident in the Davis and Guadalupe mountains of west Texas (Lockwood and Freeman 2004). The North American Breeding Bird Survey does not sample Virginia’s Warbler in Texas. Data from 93 routes in the southwest United States suggest a yearly population change of about -1.2% for the period 1980-2005 (Sauer et al. 2005). This trend suggests that local habitat conditions in the Trans-Pecos mountains will have the greatest effect on the status of this warbler as a breeder in Texas. Text by Robert C. Tweit (2007)
Harrison, H. H. 1979. A field guide to western birds’ nests. Houghton Mifflin, Boston, MA.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M University Press, College Station.
Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.
Phillipa, A., J. Marshall and G. Monson.. 1964. The birds of Arizona. University of Arizona Press, Tucson.
Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, results and analysis 1966-2005. Version 6.2 2006. USGS Patuxent Wildlife Research Center, Laurel MD < http://www.mbr-pwrc.usgs.gov/bbs>
Wise-Gervais, C. 2005. Virginia’s Warbler (Vermivora virginiae). In Arizona breeding bird atlas. pp. 464-465 (T. E. Corman and C. Wise-Gervais, eds.). University of New Mexico Press, Albuquerque.