Vireo olivaceus

Red-eyed Vireo is one of the commonest birds of the eastern deciduous woodlands. North American breeders are considered conspecific with 9 subspecies of similarly plumaged birds which breed throughout much of South America.

DISTRIBUTION. During the 1987-1992 field work for the TBBA project, observers found confirmed breeding activity for Red-eyed Vireo in the Pineywoods, Post Oak Savannah and Blackland Prairies, Coastal Prairies and Edwards Plateau regions of Texas (as described by Lockwood and Freeman [2004]). The unconfirmed record from the Guadalupe Mountains of the Trans-Pecos is probably a late migrant since Oberholser’s (1974) map shows a spring migrant specimen was taken there.

North American Breeding Bird Survey (BBS) observers found the highest relative abundance of Red-eyed Vireos in Texas in the Pineywoods region where an average of 10-30 vireos were detected per 40 km (25mi) route. (Sauer et al. 2005).

Outside Texas, Red-eyed Vireo breeds from northwest Canada east to Newfoundland and south to Washington, Oregon, Idaho, Wyoming, Colorado, Oklahoma, and the Gulf Coast states. All Red-eyed Vireos breeding in North America winter in South America, primarily in the Amazon basin (Cimprich et al. 2000).

SEASONAL OCCURRENCE. Migrant Red-eye Vireos are present in Texas from about March 2 to June 10. They are very common to uncommon in the east and rare to very rare west from early April to mid May. The breeding season extends from late April to early August (based on egg dates from May 6 to June 18 and young in a nest July 18. Extreme dates for fall migrants are July 6 to November 16 with the peak between mid-August and mid-October. Red-eyed Vireos are absent in winter (Oberholser 1974, Lockwood and Freeman 2004).

BREEDING HABITAT. Red-eyed Vireo breeds in Texas from near sea level to 600 m (2000 ft) in tall deciduous trees preferably near water, defined by the Colorado Breeding Bird Atlas as lowland deciduous riparian (Oberholser 1974, Chace 1998).

The Red-eyed Vireo’s deep cup nest is generally suspended from a horizontal fork of a slender tree limb, usually 1.5-3 m (5-10 ft) above ground. It is built by the female in about 5 days, using grasses, paper, bark strips, rootlets and vine tendrils. The outside is covered with spider silk which is also used to attach the nest to supporting twigs. The outside is often decorated with lichens. The outer diameter is 7×7.5 cm (2.8×3 in), height 5-8 cm (2-3.2 in), inside diameter 5.4×6 cm (2.2×2.4 in and cup depth 3-5.2 cm (1.2-2.1 in).

The female usually lays 3-4 (range 1-5) smooth white eggs with little gloss (see Harrison [1979] for photo of markings). The female does most or all of the incubation which nay start before the last egg is laid. Incubation lasts 12-14 days and young birds leave the nest 10-12 days after hatching. In Texas, 2 broods per season are possible. Red-eyed Vireo is one of the most frequent hosts of Brown- headed Cowbird (Molothrus ater) and parasitism by Bronzed Cowbird (M. aeneus) has also been reported (Harrison 1979, Cimprich et al. 2000).

STATUS. Lockwood and Freeman (2004) rate Red-eyed Vireo as a common to uncommon summer resident in the eastern half of Texas.

BBS data from 52 routes in this state provide a 95% confidence interval (There is a 95% chance that the actual population trend will be between these two numbers.) of-0.7 to +2.4% population change per year for the period 1966-2004. For the species total range in North America, data from 2450 routes provide a statistically significant +1.3% population trend for the same period (Sauer et al 2004). These trends are encouraging for the status of Red-eyed Vireo in Texas.

Text by Robert C. Tweit (2006)

Literature cited.

Chace, J. F. 1998. Red-eyed Vireo (Vireo olivaceus). In Colorado breeding bird atlas, pp. 310-311 (H. E. Kingery, ed.). Colorado Bird Atlas Partnership< Denver.

Cimprich, D. A., F. R. Moore and M. P. Guilfoylet. 2000. Red-eyed Vireo (Vireo olivaceus). In The birds of North America, No. 527 (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.

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.

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).