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Kentucky warbler

Kentucky warbler (Geothlypis formosa) [female]
Photo © Rob Curtis/The Early Birder

Kentucky warbler (Geothlypis formosa) [male]
Photo © Rob Curtis/The Early Birder

Features and Behaviors

The Kentucky warbler averages five and one-half inches in length. Its belly feathers are yellow, and the back feathers are gray-green. A black line in front of each eye extends and drops behind the eye as “sideburns.” A yellow line in front of each eye continues back to encircle the eye.

The Kentucky warbler is a common migrant and summer resident in the southern two-thirds of Illinois. It winters from Mexico to northern South America. Spring migrants begin arriving in April. This warbler migrates at night. Nesting takes place from May through July. The nest is built on or near the ground and is made of grasses, rootlets and other plant materials. Three to six white eggs with red-brown markings are laid by the female. She alone incubates the eggs for the 12- to 13-day incubation period. One brood is raised per year. Nests are often parasitized by the brown-headed cowbird that deposits an egg that the Kentucky warbler will hatch and raise, taking food and care away from its own young. Fall migration begins in August. This bird lives in upland or bottomland forests, especially in ravines. Its song is a rapid series of “ca-che” or “tory-tory-tory” notes. It eats insects.

Reasons for Concern

Habitat destruction and forest fragmentation are important factors in this species’ decline in Illinois.

Illinois Range


​Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Parulidae

Illinois Status: common, native