The Swainson's Warbler is unusual in that it breeds in two entirely different habitat types, both of which occur in Tennessee. In the western part of the state it occupies bottomland hardwood forests with cane or dense vine tangles; in the east it is found in the mountains in dense evergreen undergrowth of moist forest ravines. This is a secretive bird and if it weren't for its loud ringing song, it would largely go unnoticed. It arrives in Tennessee in mid- to late April and departs in early September. The breeding range includes the southeastern United States from eastern Oklahoma to northern Florida, and the winter range includes the Caribbean islands and the Yucatan Peninsula of Mexico. Losses to bottomland hardwood breeding habitat and wintering habitat have led this species to be considered of high conservation concern by Partners in Flight and placed on the National Audubon Watchlist.
Description: Both the male and female have a rust-colored cap on the head, are brownish-olive above and dull white below, and have a whitish line over the eye.
Voice: The song is a series of clear slurred notes descending with an emphatic ending. It is somewhat similar to the song of the Louisiana Waterthrush.
Habitat: In West and Middle Tennessee the Swainson's Warbler is found in wooded swamps with canebrakes or dense vine tangles, specifically the Mississippi River valley and the Hatchie River basin. In the mountains of East Tennessee, it inhabits rhododendron thickets along mountain ravines.
Diet: Primarily insects in, on, or near the ground.
Nesting and reproduction: Males will usually return to the same territory annually.
Clutch Size: Usually 4 eggs, range 2 to 5.
Incubation: The female incubates the eggs for 13 to 15 days.
Fledging: Both parents feed the young, which fledge in 10 to 12 days.
Nest: The female builds the bulky cup-nest of dry leaves and sticks, and lined with grasses, moss, and rootlets. It is placed low to the ground and resembles fallen leaf debris, and is very large compared to the nests of other warbler species.
Status in Tennessee: The Swainson's Warbler is an uncommon migrant and summer resident in East and West Tennessee, and rare in Middle Tennessee. The bird is most numerous in the Mississippi and Hatchie River basins. Scattered birds are found along drainages on the Cumberland Plateau up through the mountains of East Tennessee. It arrives in late April and departs by early September. Due to the loss of breeding habitat, especially in West Tennessee, the species is listed as In Need of Management by the state.
Dynamic map of Swainson's Warbler eBird observations in Tennessee
- The Swainson's Warbler was first described by John James Audubon in 1834 and named after his friend, the ornithologist William Swainson.
- Females will stay on the nest upon close approach and may fake injury to distract would-be predators away from the nest.
- Swainson's Warbler breeding territories vary greatly in size and have been recorded from 7.4 to 44.5 acres. One research study found that the territory varies in size during the season, being largest when the male first arrives in the spring, smallest during nest building and incubation, and increasing again once the eggs hatch.
- Swainson's Warblers spend the winter primarily in the Caribbean basin, especially Jamaica and Cuba, and populations are threatened by habitat destruction in these countries.
Obsolete English Names: Swainson's Swamp-Warbler
Best places to see in Tennessee: Meeman-Shelby Forest State Park, Hatchie NWR, and other forested tracts in the Mississippi River and Hatchie River basins. Also Northern Cumberland WMA, Rock Creek Recreation Area in the Cherokee National Forest, and Great Smoky Mountain National Park
For more information:
National Audubon Society Watchlist, Swainson's Warbler
Brown, R. E. and J. G. Dickson. 1994. Swainson's Warbler (Limnothlypis swainsonii), The Birds of North America (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. of Tennessee Press, Knoxville.
Robinson J. C. 1990. An Annotated Checklist of the Birds of Tennessee. Univ. of Tennessee Press, Knoxville.
Sibley, D. A. 2000. The Sibley Guide to Birds. A. A. Knopf, New York, NY.