Most migrating bird species in Teller County are insect eaters that leave in the winter when their primary food source is unavailable. Vireos return to our area in early May when more insects are emerging. The plumbeous vireo prefers to hang out in forests and woodlands below 8000 feet, so while some squeak into the county they are mostly found at lower elevations in the mountains and foothills. One reliable place I have observed them is in open ponderosa pine and aspen woodlands in the Manitou Lake area, which hovers at around 7750 feet. They also can be found in riparian woodlands and Gambel oak shrublands with scattered trees. Plumbeous vireos tend to leave Teller by mid-September.

Vireos are stout, sparrow-sized birds. As compared to warblers, their beaks are thicker and plumage duller. They also move more slowly than warblers, lazily foraging along branches for insects. Species identification is helped by the presence or absence of features like wing bars and eye markings. Vireos are seen alone or in pairs and the other vireo likely to be seen locally is the warbling vireo.

The plumbeous vireo is gray above and white below with pale wing bars. The best feature to secure the ID is white eye rings with a connecting white line that extends over the beak, making it appear like they are wearing spectacles. In the fall they may show a tinge of yellow on their sides. The sexes appear similar. The lazy song of the plumbeous vireo consists of a series of short slurred whistles with distinct pauses between the notes. They may also utter strange buzzes and chatters.

The plumbeous vireo was formerly known as the solitary vireo until it was split into three distinct species (plumbeous, Cassin’s and blue-headed) that are endemic to certain regions. The plumbeous inhabits the southern Rocky Mountains, while the Cassin’s breeds in the Pacific Northwest and the blue-headed in the eastern U.S. Both the Cassin’s and blue-headed Vireos are possible as migrants in Colorado, passing through in the spring and fall.

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Notable reports in March from the Woodland Park yard area. FOS = First of Season for returning migrants.

• Turkey vulture- FOS on March 31
• Canada goose- a few flyovers
• Eurasian collared-dove- one or two around most of the time, singing on March 24
• Downy woodpecker- two on March 18
• Williamson’s sapsucker- FOS on March 25
• Western bluebird- a few around most of the time, FOS on March 10
• American robin- a few around most of the time, sing on March 11
• White-breasted nuthatch- one or two around most of the time
• Brown creeper- one singing on March 18
• Dark-eyed junco- winter subspecies: pink-sided, Oregon, slate-colored- one or two of each around most of the time
• Evening grosbeak and pine siskin- a few around most of the time
• Cassin’s finch- a few around most of the time, singing on March 12, flock of 12 on March 30

Joe LaFleur studied wildlife biology and communications at Colorado State University. He is author of the book Mountain Birds of Teller County and creator of “Better Birdwatching,” a DVD series on North American birds. His betterbirdwatching.com website features a Teller County Bird Checklist and Blog. Contact him with questions and feedback at joe@betterbirdwatching.com.