About Vireo bellii Audubon, 1844
Bell's vireo, scientifically named Vireo bellii Audubon, 1844, has the following physical measurements: total length ranges from 4.5 to 4.9 inches (11.5 to 12.5 cm), weight ranges from 0.3 to 0.3 ounces (7.4 to 9.8 g), and wingspan ranges from 6.7 to 7.5 inches (17 to 19 cm). In its breeding range, Bell's vireo frequently occupies dense shrubbery located in riparian zones or other areas close to water. All four subspecies of Bell's vireo favor willow trees (Salix spp.) as nesting sites, though mesquite and seep-willow (Baccharis salicifolia) are commonly used for nesting in western regions of the range. Bell's vireos build hanging nests that are suspended between the ends of low tree branches. Nests of this species are often parasitized by brown-headed cowbirds, which lowers the overall rate of nest success.
