Cliff Swallows are highly social and nest in colonies numbering into the thousands. They were once strictly a bird of the west, attaching their gourd-shaped mud nests to vertical surfaces underneath horizontal rock ledges. However, in the past 100 to 150 years humans have been constructing alternative nest sites such as buildings, bridges etc., and Cliff Swallows have correspondingly extended their range to the east. They likely started nesting in Tennessee with dam and lock construction in the early 1900's and are now found across much of the state. Their breeding range now extends from western Alaska eastward to New England, and southward through the central United States to southern Mexico. Cliff Swallows migrate to southern South America for the winter.
Description: The two most distinctive features of this square-tailed swallow are the bright white forehead, and tawny rump. The face is chestnut, the throat is dark, the back and top of the head are a dark dull bluish-black, and it is dull white below. Adults and juveniles are similar in appearance, but juveniles (June-December) have brown, not blue-black backs, lack chestnut on the face, and have a duller patch on the forehead.
Weight: 0.74 oz
- Barn Swallows have similar coloration patterns, but have a long, forked tail.
- Cave Swallows, extremely rare in West Tennessee, are similar but usually have a chestnut forehead and a light throat.
Habitat: In Tennessee, Cliff Swallows usually nest on dams, and bridges over large reservoirs or large to medium sized rivers.
Diet: Flying insects.
Nesting and reproduction: While Cliff Swallows frequently nest on barns elsewhere in their range, they only do this in northeastern Tennessee. Most colonies in the state are on concrete dams and bridges; nesting on natural surfaces is rare.
Clutch Size: 2 to 6 eggs, with 3 most common.
Incubation: Both adults incubate the eggs for 14 to 16 days.
Fledging: The male and female tend the nestlings, which fledge when about 24 days old.
Nest: Both adults build the distinctive, gourd-shaped mud nests. It is constructed of mud pellets, with a small entrance tunnel on one side, and lined with grass. Nests are placed on a vertical wall, usually just under an overhang. In Tennessee, most nests are on a human-made surface such as a bridge or dam; nest heights range from 7 to 66 feet above the water.
Status in Tennessee: The first published Cliff Swallow nesting records were in 1936 in Stewart, Montgomery, and Decatur Counties though they likely started nesting in the state much earlier. Cliff Swallows are now a locally common summer resident across Tennessee, and their numbers continue to grow. Cliff Swallows are present in the state from early April to early September.
Dynamic map of Cliff Swallow eBird observations in Tennessee
- The Spaniard Silvestre Velez de Escalante first mentioned the Cliff Swallow and its colonial breeding habits in September 1776 when he encountered large numbers in the Wasatch Range of Utah.
- The first "documented" Cliff Swallow nests in Tennessee were in 1936 on 3 locks on the lower Cumberland River in Stewart and Montgomery Counties, and on Swallow Bluff on the Tennessee River, Decatur County. However, they likely were nesting in the state earlier than that. Workers at the lock reported seeing nests starting in 1916, and the very name "Swallow Bluff" suggests that the birds had been present there for many years. Since 1936, the numbers of colonies in the state has continued to grow.
- The subspecies of Cliff Swallow nesting in Tennessee is Petrochelidon pyrrhonota ganieri, named after Tennessee ornithologist Albert F. Ganier (1883-1973). The type specimen came from Swallow Bluff, Decatur County.
- The largest colony ever reported in Tennessee was 2,500 nests in Decatur County in 1958. Current colonies average between 100 and 200 nests.
- Cliff Swallows will occasionally lay their eggs in neighboring nests and have been observed actually moving eggs from their own nest into others.
- The oldest known Cliff Swallow in the wild was 11 years, 10 months old.
Obsolete English Names: eave swallow, Republican swallow
Best places to see in Tennessee: Cliff Swallows nest under many large and medium sized bridges across Tennessee. Colonies may be found along most of the major rivers and tributaries across the state. Some of the best specific locations to view them:
1. Under the I-40 bridge at the Tennessee River. Exit I-40 at exit 137 and take the gravel road that parallels the interstate along the north side of the highway. This road goes under the bridge. Lat-Long: 35.866395,-87.937213
2. The I-155 bridge over the Mississippi River in Dyer Co. also has about 3,000 pairs of birds nesting. Access this area from Bungie Rd off of the Great River Rd (Hwy 181). Lat-Long: 36.110559, -89.61017
3. Most medium to large bridges in the state now have colonies.
In fall, powerlines near the Mississippi River in west Tenessee are great places to find them concentrating. The old Tiptonville Ferry Landing is a great place to easily see multiple species of swallow in late summer. Other areas like Moss Island WMA in Dyer Co can be a good place for post breeding swallow gatherings.
For more information:
The Cliff Swallow (Petrochelidon pyrrhonota) in Tennessee by Fred J. Alsop, III,
National Audubon Society Historical Account
Brown, C.R. and M.B. Brown. 1995. Cliff Swallow (Petrochelidon pyrrhonota), The Birds of North America (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
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.