Small, grayish; nondescript. One or two light wing bars, pale yellowish-washed sides. Distinguished from Warbling Vireo by the wing bar(s) and whitish eye-ring. Flicks tail.
Willows, streamsides. Breeds in low dense growth, especially in second-growth scrub or brushy fields in Midwest, streamside thickets in Southwe
st, but also locally in chaparral, woodland edges, or scrub oaks. Winters in the tropics in dense low scrub, mostly near water.
Habitat loss and modifications through agricultural spread, logging and housing developments have caused declines and continue to threaten the species. Secondarily, rates of brood parasitism by Brown-headed Cowbirds (Molothrus ater), have caused reductions in breeding populations in south-west USA
In breeding season, feeds almost entirely on insects, especially large ones, including caterpillars, stink bugs, wasps, bees, and weevils, also many others. Eats some spiders and a very few berries. Winter diet unknown.
Behavior: Usually forages in low brush, within 12 of ground, but occasionally will feed much higher. Searches for insects among fol
iage, sometimes hovering while picking items from leaves or twigs; occasionally flies out to catch insects in midair.
This species has undergone moderately rapid declines and hence is considered to be Near Threatened. [conservation status from birdlife.org]
Male defends nesting territory with incessant singing. In courtship, male may chase female; members of pair often posture and display to each other during early stages of nest building.
Nest: Site is in low shrub or sapling, usually 2-5 above the ground and placed in fork of horizontal twig. Nest (built by both sexes) is a small hanging cup, its rim firmly woven into fork; made of
grass, weeds, plant fibers, leaves, bark strips, bound with spider webs. Inside may be padded with feathers, plant down, moss, then lined with fine grass. Spider egg cases often added to outside.
Clutch 3-5, usually 4. White, usually with dots of brown or black concentrated at larger end. Incubation is by both parents (but females do more), about 14 days.
Young: Both parents bring food for the nestlings. Young leave the nest 11-12 days after hatching.
Central and southwestern United States, northe
rn Mexico. Winters to Nicaragua. Migration: Migrates mostly at night. Arrives in Southwest in March but does not reach northernmost nesting areas until May.
- spanwidth min.: 17 cm
- spanwidth max.: 19 cm
- size min.: 11 cm
- size max.: 12 cm
- incubation min.: 13 days
- incubation max.: 15 days
- fledging min.: 11 days
- fledging max.: 13 days
- broods 1
- eggs min.: 3
- eggs max.: 5
- Conservation Status
- Vireo bellii bellii
- Vireo bellii medius
- Vireo bellii arizonae
- Vireo bellii pusillus
- Vireo bellii
- NA, MA sc, sw USA to Nicaragua