Cassin's Vireo

About the Cassin's Vireo

Cassin's vireo (Vireo cassinii) is a small North American songbird, ranging from southern British Columbia in Canada through the western coastal states of the United States, including California, Oregon, and Washington. The Cassin's Vireo moves down Western United States forests in its migration. During its migration in early spring and late fall, it spends the winter in regions from southern Arizona (the Sonoran Desert) to southern Mexico, including parts of Baja California and the Pacific coast of Mexico.

The vireo is 11–14 cm (4–6 inches) long. It has a grayish olive head, back, and flanks, with whitish underparts. One of its distinctive features is the solid white "spectacles" around its eyes, along with white wing bars. These markings set it apart from other similar species like the plumbeous vireo and the blue-headed vireo.

Cassin's vireo is known for its persistent song, which consists of short, rough-whistled phrases of several notes.These phrases are 2 seconds apart and often alternate between ending on high and low notes, creating a "question-and-answer" pattern. The Cassin's Vireo is known to sing for an extensive duration of time. Hearing... Wikipedia →