Vireo plumbeus

The former “Solitary Vireo” was split into 3 species after completion of the TBBA field work. The map below carries the names of all 3 species but we can assume that the 2 confirmed breeding records on the map represent Plumbeous Vireo since Lockwood and Freeman (2004) do not report breeding in Texas for either Cassin’s (V. cassinii) or Blue-headed (V. solitarius) vireos. Both these species migrate through the state, but their breeding ranges are hundreds of miles from this state (James 1998, Goguen and Curson 2002).

DISTRIBUTION. During the 1987-1992 field work for the TBBA project, observers found Plumbeous Vireo breding in the Davis and Guadalupe mountains of Trans Pecos Texas where Lockwood and Freeman (2004) characterize them as summer residents. The 3 unconfirmed records in the Edwards Plateau region are difficult to categorize. They might represent new breeding sites in an area where breeding has not been reported before (Oberholser 1974), or they might be migrants of any of the 3 ex-Solitary Vireo subspecies. Further investigation in this area would be helpful.

Elsewhere the Plumbeous Vireo breeds from Idaho, Montana and western South Dakota south through the highlands of Mexico to the Isthmus of Tehuantepec with isolated populations in the highlands of Chiapas (Mexico), Belize and Guatemala. In winter breeders from the United States move south to Mexico with many highland breeders there joining them along the west coast of the mainland. Some Plumbeous Vireos also winter in Baja California Sur (Howell and Webb 1995, Sauer et al. 2005).

SEASONAL OCCURRENCE. The species is a common migrant through the Trans Pecos region and uncommon to rare in the High Plains and western Edwards Plateau regions. Plumbeous Vireo moves through these regions from early April to mid-May. It probably breeds from mid-May to early August in the Trans Pecos. Migrants move south from early September to early November. In winter Plumbeous Vireo is rare in the Trans Pecos with occasional records elsewhere in Texas.(Oberholser 1974, Lockwood and Freeman 2004).

BREEDING HABITAT. Plumbeous Vireo breeds in Texas fro 1500 to 2400 m (5000-8000 ft) on slopes covered with oak, juniper and pine and in riparian areas containing oak, maple and occasional cottonwood (Oberholser 1974). In Arizona and Colorado, the two closest states with habitat data available from Breeding Bird Atlases, the species prefers pinyon-juniper, riparian, pine-oak and ponderosa pine (total74% in Arizona, Wise-Gervais 2005). In Colorado Plumbeous Vireo nests in pinyon-juniper (with or without ponderosa pine), deciduous riparian and shrub oak habitats (total 74%, Chace 1998).

Harrison (1979) reports Plumbeous Vireo nests in southern Arizona are usually placed in evergreen oaks 1-3 m (3-10 ft) above ground. The nest is a basket suspended from a twig fork on a horizontal branch and built of inner bark strips, soft plant fibers, grasses, forb stems, rootlets and hair. The outside is often decorated with moss, conifer needles, fine grasses or paper. The nest is generally bulkier and more loosely constructed than those of other vireos. The outside diameter is 9×12 cm (3.5×4.7 in), height 8.5 cm (3.4 in), inside diameter and cup depth 6 cm (2.3 in).

The female usually lays 4 (range 3-5) smooth, dull white to creamy white eggs (see Harrison [1979] for photo of markings). Both sexes incubate the eggs and the male may sing from the nest while incubating. The eggs hatch about 14 days after the last egg is laid.. Nestlings leave the nest about 13-14 days after hatching. Plumbeous Vireos raise one brood per season and are extensively parasitized by Brown- headed Cowbirds (Molothrus ater) and occasionally by Bronzed Cowbird (M. aeneus; Harrison11979, Curson and Goguen 1998).

STATUS. Lockwood and Freeman (2004) consider Plumbeous Vireo a common summer resident in the Davis and Guadalupe mountains, but rare in the Chisos Mountains. Oberholser’s map (1974) shows breeding evidence in Culbertson, Davis, Presidio and Brewster counties, but not in the Edwards Plateau region.

Breeding Bird Survey data for this species in Texas are insufficient to produce a population trend. Across the United States, data from 273 routes on which Plumbeous Vireo was detected produced a 95% confidence interval (There is a 95% chance that the actual population trend will be between these two numbers.) of -2.1 to +1.5% population change per year for the period 1966-2004 (Sauer et al. 2005) This trend estimate suggests that any population change across this species breeding range in the United States has been relatively small in recent years.

Text by Robert C. Tweit

Literature cited.

Chace, J. F. 1998. Plumbeous Vireo (Vireo plumbeus). In Colorado Breeding Bird Atlas, pp. 306-307 (H. E. Kingery, ed.), Colorado Bird Atlas Partnership, Denver.

Curson, D. R. and C. B. Goguen. 1998. Plumbeous Vireo (Vireo plumbeus). In The Birds of North America, No. 366 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Goguen, C. B. and D.R. Curson.. 2002. Cassin’s Vireo (Vireo cassinii). In The Birds of North America, No. 615 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Harrison, H. H. 1979. A field guide to western birds’ nests. Houghton Mifflin, Boston, MA.

Howell, S. N. G. and S. Webb 1995. A guide to the birds of Mexico and northern Central America. Oxford University Press, New York.

James, R. D. 1998. Blue-headed Vireo (Vireo solitarius). In The Birds of North America, No. 379 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

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, Vol. 2. University of Texas Press, Austin.

Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, results and analysis 1966-2004. Version 2005.1. USGS Patuxent Wildlife Research Center, Laurel MD (Web site, http://www.mbr-pwrc.usgs.gov/bbs).

Wise-Gervais, C. 2005. Plumbeous Vireo (Vireo plumbeus). In Arizona Breeding Bird Atlas. pp. 342-343 (T. E. Corman and C. Wise-Gervais, eds.), University of New Mexico Press, Albuquerque.