0 the yellow-throated vireo , vireo flavifrons , is a small american songbird .
1 adults are mainly olive on the head and upperparts with a yellow throat and white belly; they have dark eyes with yellow "spectacles" .
2  the tail and wings are dark with white wing bars .
3  they have thick blue-grey legs and a stout bill .
4 their breeding habitat is open deciduous woods in southern canada and the eastern united states .
5 these birds migrate to the deep southern united states , mexico and central america .
6  they are very rare vagrants to western europe .
7  there is one record from britain in kenidjack valley cornwall september 20-27 1990. there is also a sight report from germany{citation needed|date=september 2007} .
8 they forage for insects high in trees .
9  they also eat berries , especially before migration and in winter when they are occasionally seen feeding on gumbo-limbo (bursera simaruba) fruit .
10  they make a thick cup nest attached to a fork in a tree branch .
