ID Keys: White on face with dark eye-line,
yellowish underparts (brightest
on upper-breast), greenish-gray upperparts.
The Philadelphia Vireo was first discovered in
Philadelphia in the 1940s, but is only a migrant through that area. The
vast majority summer in southern Canada and are only migrants through the
eastern half of the United States. They are most often found high in the
treetops and rarely sing during migration, so are perhaps widely overlooked in
spring in the U.S.
Habitat
Uses deciduous or mixed woodlands during the summer breeding season, especially near woodland edges or in young second-growth forest. Uses open woodlands in the tropics during the winter.
Diet
Primarily feeds on insects in all seasons. Will also eat spiders, snails, fruits, and berries.
Behavior
Philadelphia Vireos are often found high in the forest canopy, but they will also forage lower in the canopy or in shrubby undergrowth. They will sometimes flycatch, observing from a perch on a branch and flying out to catch passing insects.
Breeding
Non-breeder in South Dakota. The Philadelphia Vireo breeds mainly in boreal and mixed forests of Canada and the northern United States, especially in areas with aspens, birches, and other deciduous trees. It builds a small hanging cup nest suspended from a forked branch, woven from grasses, bark strips, spider silk, and plant fibers.
Song
The Philadelphia Vireo sings a rich, deliberate series of whistled phrases that resemble the song of the Red-eyed Vireo but are generally slower, sweeter, and less hurried. Its song is often rendered as short paired phrases with rising and falling tones repeated from concealed perches high in trees.
Migration
Primarily summers in southern Canada, locally in New England and the upper Great Lakes area. Winters in the tropics.
Warbling Vireo , Tennessee Warbler. The Philadelphia Vireo is more yellow below than the Warbling Vireo and usually shows a darker lores area that gives a faintly spectacled appearance, while Warbling Vireos appear plainer-faced and grayer overall. Compared to the Tennessee Warbler, Philadelphia Vireos are chunkier with a thicker hooked bill and slower movements, whereas Tennessee Warblers are slimmer, more active, and have a much finer pointed bill.
Conservation Status
The Philadelphia Vireo remains fairly common across much of its boreal breeding range and is generally considered a species of low conservation concern. However, habitat loss and fragmentation in breeding and wintering areas, along with threats to migratory stopover habitats, may affect some regional populations. The IUCN considers the Philadelphia Vireo to be a species of "Least Concern" .
