Black-throated Blue Warbler, Setophaga caerulescens
The male and female of this species are so different in appearance that John James Audubon, and Alexander Wilson before him, described them as belonging to different species.
The male Black-throated Blue Warbler is among the most distinctive of warblers, with his strikingly blue back and black face, and its zoo-zoo-zoo-zeee song is one of the easiest warbler songs to learn . This bird is found in the interior of large mature forests where it forages in the lower and mid-levels of the canopy plucking insects from the undersides of leaves.
The Black-throated Blue Warbler breeds from southeastern Canada and New England southward along the Appalachian Mountains to northern Georgia. In winter, it travels to the Caribbean. Since the Black-throated Blue Warbler only breeds in the eastern mountains of Tennessee and migrates along the eastern seaboard, it is rarely seen in Middle and West Tennessee.
Description: Both the male and female have a small white wing-patch visible on the edge of their folded wing, otherwise they look very different. The male is a deep slate blue above with a black face, throat, and flanks; his chest and belly are white, and he maintains this plumage year round. The female is overall dull grayish olive-green, with a yellowish to cream colored stripe over the eye.
Weight: 0.36 oz
Voice: The song is a distinctive slow, raspy, 4 or 5 note zoo-zoo-zoo-zeee, with the last note slurred upward. Males will sing well into the summer in Tennessee.
- The male is unmistakable, and no other warbler has a white wing-patch similar to that of the Black-throated Blue Warbler.
- The female resembles both the Tennessee and Orange-crowned Warbler, but neither of them have the white patch on the wing.
Habitat: Black-throated Blue Warblers breed in large tracks of mature deciduous and mixed forest, with a dense understory, often in mountainous terrain. During migration, they can be found in a variety of forest habitats including forest edge and suburban environments.
Diet: Primarily insects, but also some small fruits.
Nesting and reproduction: Males occasionally have two mates within their territory. Females are known to sometimes raise 2 broods within a season.
Clutch Size: 3 to 4 eggs.
Incubation: The female alone incubates the eggs for 12 to 13 days.
Fledging: Both parents feed the young, which leave the nest when 10 to 12 days old.
Nest: The nest is an open cup made of strips of bark, held together with spider web, and lined with finer materials. It is usually placed 1.5 to 4 feet above the ground in a dense shrub. The female is the main nest builder and it takes her 3 to 5 days to construct a nest.
Status in Tennessee: The Black-throated Blue Warbler is a fairly common migrant, and locally common summer resident, in the eastern mountains of Tennessee. Elsewhere in the state, this species is rare. Populations appear to be stable.
- Male Black-throated Blue Warblers nesting in the Appalachian Mountains have black streaks on their backs, not solid blue like other populations.
- When the "Father of American Ornithology," Alexander Wilson (1766-1813), first described the female Black-throated Blue Warbler, he thought it was a separate species and named it the Pine Swamp Warbler. Several years later, when John James Audubon painted this bird from specimens he collected in the Great Pine Swamp of Pennsylvania, he called it the same thing.
- The oldest known Black-throated Blue Warbler in the wild was 9 years, 8 months old.
- Males and females use somewhat different habitats on the wintering grounds. Males are usually found in low and mid-elevation forests and in shade coffee plantations, while the female uses more early successional sites, or shrubby habitat at higher elevations.
Obsolete English Names: pine swamp warbler
Best places to see in Tennessee: In Great Smoky Mountains National Park they are commonly found above 2,800 feet, and as low as 2,400 feet in moist cove forests. There is also an isolated population above 2,600 feet at Frozen Head State Natural Area.