Kentucky Warbler, Geothlypis formosa
The Kentucky Warbler is a bird that is more often heard than seen. Its persistent song rings through woodlands with dense understory, but is likely to only provide a brief glimpse of itself.
The Kentucky Warbler breeds primarily in the southeastern United States, and winters from southern Mexico to northern South America. It is present in Tennessee from April through October.
Description: Adults are bright olive above and bright yellow below. The distinct black and yellow face pattern includes a yellow eye-stripe that wraps around the eye forming "spectacles." The female and immature birds (July-March) are somewhat duller.
Weight: 0.6 oz.
Voice: The song is a rolling series of slightly up-slurred, musical chur-ry chur-ry chur-ry phrases. The call note is a smacking chunk.
- Not easily confused with other species because of the unique face pattern and yellow spectacles.
- Common Yellowthroat males have a broad black mask through the eye.
- The song of the Carolina Wren is similar but more varied in tone.
- The Ovenbird song is similar but the phrases are slightly down-slurred.
Habitat: Kentucky Warblers are found in relatively large forest tracts with mature trees and thick understory. They are typically absent from areas where the ground cover and understory have been disturbed by human actions or deer overbrowsing.
Diet: Small spiders, other insects, and caterpillars. In winter, may eat fruit from Cecropia trees.
Nesting and reproduction: Pairs start nesting shortly after arrival in mid-April, with peak egg laying in mid-May through early June. They typically raise only one brood, but may have a second brood if the first one fails. Kentucky Warblers are a common host of Brown-headed Cowbirds.
Clutch Size: 4 to 5 eggs, with a range of 2 to 6.
Incubation: The female incubates the eggs for 12 to 13 days.
Fledging: Young leave the nest as early as 7 days and as late as 10 days after hatching. Both adults feed the young.
Nest: The well-concealed nest is made of grass, bark shreds, weeds, and vines. It is placed on the ground in a thicket of shrubs or in a small bush, often near a forest opening.
Status in Tennessee: The Kentucky Warblers is a fairly common breeding bird and less common migrant, across Tennessee. They arrive in mid-April and depart by mid-September. The current population in Tennessee appears to be stable or declining.
- Only male Kentucky Warblers sing. Most birds have one song type, which is sung at one pitch their entire lives. The song of a neighboring male may be at a slightly different pitch, but the two birds will not "match" songs even when counter-singing.
- The probability that a Kentucky Warbler will occupy a particular moist tract of forest increases with the size of that woodland.
Best places to see in Tennessee: Mature forest tracts with developed regeneration of trees and shrubs statewide.
Mcdonald, M. V. 1998. Kentucky Warbler (Oporornis formosus), The Birds of North America, No. 324 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.
Nicholson, C. P. 1997. Atlas of Breeding Birds of Tennessee. Univ. Tennessee Press, Knoxville.
Sibley, D. A. 2000. The Sibley Guide to Birds. A. A. Knopf, New York, NY.