The rest of the world calls it spring fever, but for birders it’s FOY season. That’s shorthand for “first of year sightings,” and it’s that tantalizing time when the first rock-solid signs of spring start to gain the upper hand over frigid mornings. Some of the earliest returnees to look for are Red-winged Blackbirds, Eastern Phoebes, Tree Swallows—and that buttery ball of sunshine in the photo above.
Yellow Warblers are among the first of the spring warblers to move en masse up the North American continent in spring. They’re also among the most conspicuous—fairly easy to see as they forage about frenetically in bushes or perch at the tops of shrubs and small trees to sing loud and proud. Both males and females are bright lemon yellow, though males also have reddish-chestnut streaking on their chest. In fact, studies suggest that a Yellow Warbler’s streaking may be a sign of his behavior—the more streaking, the more aggressive a male acts toward other males.
So when can you count on seeing your first Yellow Warbler (or hearing its sweet-sweet-I’m-so-sweet song)? Naturally, it depends on where in North America you live. But Benjamin Van Doren (a Cornell undergrad) and Andrew Farnsworth of our BirdCast project delved into the eBird database to make this animated map. It shows the slow-and-then-sudden invasion of returning Yellow Warblers, day by day, from March 15 to June 15. (The data were grouped by state and the patterns should be regarded as approximate.)
Check it out—and let us know how closely it matches the date of your first sighting.
Quick Facts About Yellow Warblers
Migration: In spring Yellow Warblers depart their wintering grounds in Central America and northern South America. They typically begin reaching the southern border of the U.S. in March and early April. By May they’re setting up breeding territories in shrubby thickets and woods—particularly along streams, rivers, and wetlands—across the northern two-thirds of the continent.
Song: Yellow Warblers sing vociferously in spring and early summer, and theirs is one of the easier bird songs to learn. The common mnemonic is sweet-sweet-sweet-I’m so sweet! You can listen to its song in our Macaulay Library.
Population Status: Locally, Yellow Warbler populations can be harmed by the disappearance of their nesting habitat, such as removal of willows along creeks. And their nests are often parasitized by Brown-headed Cowbirds—that is, cowbirds sneak into Yellow Warbler nests and lay their eggs. But across their broad range, Yellow Warblers are one of the most numerous warblers in North America (with an estimated population of 90 million) and their numbers seem stable.
Learn more about Yellow Warblers in our online species guide.
Find out when other migrants are near you: Take a look at our eBird Occurrence Maps; moving range maps for over 50 species including:
And check out the cool migratory patterns for these species: