Vireo philadelphicus
The few Philadelphia Vireos that range into Banff and Jasper national parks are pioneers stretching the western range of this species, which typically breeds east of the Rocky Mountains. Even in the core of its range, this bird is difficult to observe, because it prefers to perch and sing near the tops of leafy trees. This vireo's voice resembles that of its Red-eyed cousin so much that few experts can distinguish between them with confidence. This bird bears the name of the city from which it was first collected. Philadelphia was the center of America's scientific community in the early 1800s, and much of the study of birds and other natural sciences originated in Pennsylvania.
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I.D.: Sexes similar: white eyebrow; yellow breast and flanks; grayish head; dark eye line extends to the bill; dark, olive-green upperparts; white belly; thick bill. Size: L 51/4 in. (13 cm). Range: common spring migrant, common summer resident and uncommon fall migrant in Jasper NP; uncommon fall migrant in Banff NP; vagrant in the U.S. Rockies. Habitat: willow stands in deciduous forests in the montane. Nesting: high up in a deciduous tree or shrub; basket-like cup nest hangs from a horizontal fork and is made of grass, roots, plant down and spider's silk; pair incubates 4 eggs for up to 13 days. Feeding: gleans foliage and other vegetation for invertebrates; frequently hovers to search for food in foliage. Voice: Male: song is a continuous, robin-like run of phrases: Look-up way-up Tree-top see-me Here-I-am. Similar Species: Red-eyed Vireo: black-bordered, blue-gray cap; lacks the yellow wash on the belly; song is lower pitched. Warbling Vireo: dusky eye line; lacks the yellow wash on the belly. Tennessee Warbler well-defined, gray cap; greenish back. |
