Vireo flavifrons

Male has a brilliant yellow throat, breast, and eye rings that look like spectacles. Its belly and two wing bars are white. The upper parts are olive-green with a contrasting gray rump. The female is similar to the male, and slightly paler. Fledglings are similar to adults, but paler.

NESTS: suspended between forks of slender branches, usually those growing laterally from a larger upright limb, and placed within the tree canopy. Typically eight to 13 m from ground, but range from 0.9 to 24 m. The nest is a well-made deep cup of grasses and strips of bark, woven together with spider silk and plant down. It is decorated on the outside with moss and lichens, and lined with fine grasses. The rim is incurved.

EGGS: white to cream-white and lightly spotted with shades of brown, mostly at the larger end. For additional information, see Hamel (1993), Hamel et al. (1982), Terres (1980), Harrison (1975), James (1973), Hamilton (1958), and Bent (1950).

The only spectacled vireo with bright yellow on the breast and throat only. It may be confused with Pine Warbler (DENDROICA PINUS) and Yellow-breasted Chat (ICTERIA VIRENS). The Pine Warbler has dusky streaks on its side and white tail spots. It also frequents pine woods, whereas this vireo is almost always seen in deciduous trees. The Yellow-breasted Chat lacks wing bars, is larger, and has a much longer tail. The Chat also is seldom seen away from dense thickets (Peterson 1980, Bent 1950).

BREEDING: Primarily open deciduous forest and woodland, riparian woodland, tall floodplain forest, lowland swamp forest, and less frequently, mixed forest; also orchards, groves, roadside trees. Most abundant in mature woods but also occurs in medium-aged forests and some pioneer stands; requires a high, partially open canopy and prefers woods with an intermediate tree density or basal area (Bushman and Therres 1988). Apparently has a relatively low tolerance to forest fragmentation, though this may depend on forest quality and proximity to other forested areas. Nests usually in the canopy of a deciduous tree, in horizontal twig fork, usually more than 6 m above ground (Harrison 1978).

NON-BREEDING: In migration and winter also in various forest, woodland, second growth, and mangrove habitats. In migration in more open areas and low scrub (Stiles and Skutch 1989).

Solitary in winter, probably territorial (Stiles and Skutch 1989). This bird is usually solitary or in interspecific flocks (Bent 1950). Reported as common cowbird host in some areas, but in other areas, even where both species are numerous, the vireo is relatively unparasitized. Has been known to successfully rear cowbirds to fledgling stage (Friedmann 1963). Occasionally buries cowbird eggs in nest lining, if it has no eggs of its own. Specific information on additional nest predators has not been located.

Nests from mid-April to late July (peak mid-May to late June) in the mid-Atlantic region (Bushman and Therres 1988). Clutch size 3-5 (usually 4). Incubation 14-15 days, by both sexes. Young tended by both parents, leave nest at about 15 days. Fledglings are independent in about four weeks, but remain with parents until August (Terres 1980, Harrison 1975, James 1973, Bent 1950). Males establish territories before mating occurs.

Male nest displays are apparently important to attracting mates (James 1978). Once paired, activities are confined to a smaller area than the unmated male's territory. Nest construction begins within 24 hours of pairing and takes eight days; the first egg laid on the ninth day. Both sexes participate in nest construction, although females are dominant at the nest (James 1973). Very sensitive to observations by humans during early nest building or searches. Nests or even mates will be deserted if an observer approaches within 50 m. Once nests are half built pairs will not desert when approached. Most nests are built in the upper halves of deciduous trees; mean nest heights were found to be above mean foraging heights (James 1973).

Sutton (1949) records rearing of two broods per season. No renesting unless the first clutch destroyed (James 1973). Both parents share in feeding and brooding of young. After brooding ceases, parents are intolerant of observers (James 1973). Prior to this time, Bent (1950) reports that this vireo "... is a close and steadfast sitter, allowing close approach and even handling...". Sutton (1949) reports that the male occasionally sings at all hours throughout the summer and frequently sings on the nest.