Cerulean Warbler, Setophaga cerulea
There are few birds more beautiful, harder to see, or in more trouble than the Cerulean Warbler. The beautiful sky-blue male sings his distinctive song from high in the canopy, but with time and patience, you can find him.
The Cerulean Warbler is a summer resident in Tennessee, arriving in mid-April and departing by the end of August. It prefers large areas of mature forest for nesting and breeds from northernmost Alabama to southern Ontario and west to the Great Plains.
Cerulean Warbler densities, however, are not even across this range. The area of highest concentration, where 80% of the population can be found, stretches from the Cumberland Mountains of Tennessee to the mountains of West Virginia. In fact, the highest breeding densities ever recorded for this species are in Tennessee.
This little bird weighing no more than 3 pennies makes a remarkable migration to northern South America to spend the non-breeding season. Unfortunately, the Cerulean Warbler is of high conservation concern because it is declining faster than any other eastern songbird. The primary reason for this decline is habitat loss caused by coal mining in the heart of the breeding range, incompatible forestry practices, and land clearing for development or agriculture in the breeding and wintering regions.
Description: The male is a bright sky-blue above, and white below with a dark "necklace" across the upper chest and dark blue streaking on the sides. The female is unique bluish-green above and creamy white below. She has no streaking on the back and has a white or cream-colored line over the eye. Both males and females have two white wing bars and large white spots on the underside of the tail. The undertail coverts are long, giving the bird the appearance of having a very short tail when viewed from below.
Weight: 0.33 oz
Voice: The song is made of three parts; the first part is a series of 2 to 4 buzzy notes given at one pitch, followed by higher pitched buzzy phrase and ending with a higher-pitched trill: zhee zhee, zizizizi, zzzeet. An alternate song, given at dawn and by unmated males, is less musical and lacks the final trill.
- No other North American bird is bright blue above, and white below with a chest band.
- Tennessee Warblers look similar to female Cerulean Warblers but have no wingbars or tail spots.
- Female Blackburnian Warblers are gray, not blue-green above, have streaks on the back, a distinctive face pattern, and no defined tail spots.
Habitat: Cerulean Warblers breed in mature deciduous forests with tall trees that have well-developed canopies, in a variety of forests including bottomland hardwood forests, and on the steep ridges of upland forests. They winter in broad-leaved, evergreen forests, and shade coffee plantations primarily in Venezuela and Columbia.
Diet: Primarily insects.
Nesting and reproduction: The life history of the Cerulean Warbler has been difficult to study because this bird forages and nests high in the upper canopy of tall trees.
Clutch Size: Usually 3 to 4 eggs.
Incubation: The female incubates the eggs for 11 to 12 days, with the male occasionally bringing her food.
Fledging: Both adults feed the young, which fledge in about 11 days.
Nest: The female alone builds the open cup-nest of bark fibers, grass stems, and hair, and bound together with a spider web. It is placed on a horizontal limb of a deciduous tree in the mid-to upper-canopy away from the tree trunk.
Status in Tennessee: The Cerulean Warbler is a summer resident occurring in scattered populations across the state (see Cerulean Warbler Atlas link below). It is relatively common on the steep slopes at the north end of Center Hill Lake, and at higher elevations in the Cumberland Mountains. Migrants and residents start arriving in Tennessee in mid-April and usually depart by the end of August. The Cerulean Warbler is listed as a species In Need of Management in Tennessee.
- On the wintering grounds in northern South America, Cerulean Warblers join mixed-species foraging flocks with other migrant and resident species. They are frequently found in shade coffee plantations. (You can purchase coffee from a Cerulean Warbler shade coffee reserve in Venezuela from the link below.)
Best places to see in Tennessee:
- Reelfoot Lake National Wildlife Refuge, Obion County. There is a poorly marked walking trail on the south side of Walnut Log Road with several breeding pairs.
- Meeman-Shelby Forest State Park, Shelby County. Along the Woodland Trail, also on Piersol Road, and the bluff line along the Pioneer Spring Trail.
- Edgar Evans State Park, DeKalb County. Several males can be heard along the entrance road starting at the top of the first big hill, also a couple of pairs nest along the nature trail at the Visitor's Center, and on the Millennium Trail.
- Center Hill Lake, DeKalb County. Many Cerulean Warblers nest on the steep slopes surrounding the north end of Center Hill Lake. An easy place to find them is along the driveway to the Appalachian Center for Crafts. Take Interstate 40 to Exit 273, and drive a few miles south to the east side of Hurricane Bridge.
- Frozen Head State Natural Area, Morgan County. Ceruleans can be found on virtually any trail that goes up the mountain.
- North Cumberland WMA has the highest density of nesting Cerulean Warblers in the world.