Yellow Warbler

Look for

Male: entirely canary yellow with bright rusty-red streaks on the chest and flanks. Body yellow, wings yellow-edged, tail yellow. The only Memphis warbler that's truly all-yellow. Female: paler yellow-olive, no streaks.

Size: ~5" — small warbler.

Listen for

• Song: a sweet, cheerful "sweet-sweet-sweet-I'm-so-sweet!" — 6–8 notes, rising then falling. One of the most recognizable warbler songs.

Where in Memphis

Migration only in spring (May) and fall (August-September). Doesn't breed in Memphis proper — breeds just north.

• Wolf River Greenway willows
• Ensley Bottoms wetland shrubs
• Shelby Farms willows and wetland edges
• Overton Park edges

Behavior

• Low-to-mid shrub foragers — work willows and wetland shrubs 5–15 ft up.
• Sing from open perches during migration.
• Hatch cowbird chicks but have a defense: they bury cowbird eggs under a new nest-floor and re-lay. Studies have found 6-layer Yellow Warbler nests with multiple rejected cowbird eggs buried.

Story

The anti-cowbird pioneer

Brown-headed Cowbirds lay parasitic eggs in Yellow Warbler nests. Other warblers just accept it. Yellow Warblers invented the counter-strategy: they recognize cowbird eggs and build a new nest floor on top of them, burying the egg, and lay fresh eggs on top.

Nests have been found with 3, 4, even 6 layers — each layer a cowbird egg that got buried. Every layer is a historical record of an attempted parasitism.

"Wild canary"

Old folk name, often applied to both Yellow Warblers and American Goldfinches. Both are small and yellow; goldfinch has black wings, Yellow Warbler doesn't.

Where they breed

Yellow Warblers breed across most of North America — from Mexico to the Arctic treeline. It's one of the most widely-distributed warblers. They just happen to not breed in the Memphis latitude specifically (too far south of preferred wetland willow habitat).

Fun facts

• Their all-yellow plumage is the most intensely yellow of any North American warbler.
• The red streaks on the male's chest are carotenoids from diet.
• They winter from Mexico to Peru — broad wintering range.
• Oldest known wild Yellow Warbler: 11+ years.
• The scientific name petechia refers to the small red spots on the chest ("petechiae" = small red spots).