Blue-headed Vireos, Vireo solitarius, is well named for its blue-gray head that contrasts with white “spectacles” yellow sides, white wing bars, a greenish back and white belly and throat.
Adults are mainly olive on the upperparts with white underparts and yellowish flanks; they have a grey head, dark eyes with white “spectacles” and white wing bars. They have a stout bill and thick blue-grey legs.
This bird, along with the Cassin’s Vireo and Plumbeous Vireo, were formerly known as the Solitary Vireo.
Distribution:
Their breeding habitat is open mixed deciduous and coniferous woods in Canada east of the Rockies and the northeastern United States. They migrateto the southern United States south to Central America.
The larger southern birds move only short distances to wintering areas from southeastern Virginia across Gulf Coast states to Texas.
Breeding:
Blue-headed Vireos typically breed in forests of both deciduous and evergreen trees. Because the deciduous trees have not leafed out when the vireos arrive on their breeding grounds, most courtship nests and first breeding nests are built in evergreen hemlock trees. Their dependence upon hemlocks may prove troublesome for the vireo because this common tree is being decimated by an introduced Asian insect, the hemlock wooly adelgid (an invasive pest that has killed vast numbers of hemlock trees in the eastern United States). After deciduous trees, such as maples and oaks, are in leaf, Blue-headed Vireos expand their preference to include many other tree species.
They build a bulky cup nest suspended from a fork in tree branch – about 1 – 5 meters above ground. The male helps participates in incubating the eggs. The cooperative nesting behavior of Blue-headed Vireo pairs is unusual among migratory birds. Male vireos build nests and incubate eggs as much or more than their mates. Although only males sing, both sexes are highly vocal and continually give soft whinneys, squeaks, and “chir” calls to one another. Also unusual among migratory birds is the fact that females do not accept or attempt to gain extra-pair fertilizations, even though males do not guard females against other males.
Nesting success is low (only 10-30% of nests produce young) and many pairs produce 3 – 5 clutches a year. The eggs or young fall prey to predators such as blue jays, crows and squirrels. The presence of nearby nesting Cooper’s Hawks may protect vireos from predation by jays and crows because Cooper’s Hawks eat jays and crows.
Brown-headed Cowbirds often lay their eggs in the deeply cupped vireo nest, oftentimes covering the vireo nestings, which then die through starvation
Diet:
Insects, particularly caterpillars, Hemiptera (true bugs) and beetles. Blue-headed Vireos will also eat fruit, especially during migration and on their tropical wintering quarters.
Song / Call:
Their deliver a pleasant song, contrasting with the harsh phrases of its close relative, the Yellow-throated Vireo.
