**Description:** A small, plain warbler with a thin, sharp bill and a short tail. Primarily olive-green with a pale eyebrow and white undertail.
**Size & Weight:** 4.3–5.1 inches long. Weighs 0.3–0.5 oz.
**Identification:** Lacks wing bars and tail spots. They are one of the plainest warblers in the region.
**Behavior:** Known for a very loud, rapid, shivering song that is surprisingly powerful for such a small bird.
**Habitat:** Seen high in the deciduous canopy during migration; they breed in boreal forests to the north.