About Vireo philadelphicus (Cassin, 1851)
Adult Philadelphia vireos (Vireo philadelphicus) are mainly olive-brown on the upperparts, with yellow underparts, dark eyes, and a grey crown. They have no wing bars and no eye ring; a dark line runs through their eyes, with a white stripe just above the eyes. They have thick blue-grey legs and a stout bill. This species is similar in appearance to the warbling vireo, but can be reliably told apart by the Philadelphia vireo’s much yellower underparts and dark lores. Their breeding habitat is the edges of deciduous and mixed woods across Canada. They build a basket-shaped cup nest in the fork of a tree branch, usually placed relatively high up. The female lays 3 to 5 lightly spotted white eggs. Incubation, which is done by both parents, lasts up to 14 days. These birds migrate to Mexico and Central America. The Philadelphia vireo is a very rare vagrant to western Europe. It is unlikely to visit Philadelphia except during migration. They forage for insects in trees, sometimes hovering or flying to catch insects mid-flight. They also eat berries, especially before migration. The songs and calls of the Philadelphia vireo consist of three to five repeated notes: weeezh weeezh weeezh. They are very similar to the calls of the red-eyed vireo, but have slightly longer pauses between phrases and higher notes.
