Western Warbling Vireo

Overview
ID info
Life History
Maps
Sounds

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ID Info

Adult

Western Warbling Vireo by Steve Wickliffe / Macaulay Library

Vireos

Western Warbling VireoVireo swainsoni

ORDER: Passeriformes
FAMILY: Vireonidae

HabitatOpen Woodlands
FoodInsects
NestingTree
BehaviorFoliage Gleaner
ConservationNot Evaluated

Basic Description

The Western Warbling Vireo’s squeaky, boisterous song is a common sound in the woodlands and river corridors of western North America—and a great way to locate this easily overlooked songbird. This gray-and-white denizen of cottonwoods and poplars looks very similar to its eastern counterpart, the Eastern Warbling Vireo. Western Warbling Vireo typically has a slightly smaller bill and a more extensive white line above the eye, but song is the best way to separate these two lookalike species.

More ID Info

Year-roundBreedingMigrationNonbreeding

Range map provided by Birds of the World

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Find This Bird

Look for Western Warbling Vireos in aspen forests and in woodlands (often cottonwood) along streams, where they are a common breeder. You will find them most readily by listening for their distinctive song.

Other Names

Vireo Gorjeador Occidental (Spanish)
Viréo de Swainson (French)

Cool Facts
- In 2025, ornithologists split Warbling Vireo into two species—Eastern Warbling Vireo and Western Warbling Vireo—based on subtle differences in measurements, plumage, and song, as well as genetic differences.
- Western Warbling Vireos have a good name—males and occasionally females sing a fast, up-and-down, rollicking song that suits the word “warbling.” The early twentieth century ornithologist William Dawson described the song this way: “fresh as apples and as sweet as apple blossoms comes that dear, homely song from the willows.”
- Brown-headed Cowbirds sometimes lay their eggs in the nests of Eastern and Western Warbling Vireos. However, female Eastern Warbling Vireos are adept at puncturing and ejecting most of the cowbird eggs they find. This makes Eastern Warbling Vireo the smallest species known to reject Brown-headed Cowbird eggs in this way. Curiously, Western Warbling Vireos are much less likely to reject cowbird eggs.
- The longest-lived Western Warbling Vireo on record—a male that was originally banded in July 1966—was at least 13 years, 1 month old when it was recaptured and rereleased during banding operations in California in 1978.