Black-throated Green Warbler (BTNW)
Setophaga virens
Range
Black-throated Green Warblers breed mainly in northeastern North America and southern Canada. A separate population has been identified in the Ozarks of northwest Arkansas. During winter, they migrate primarily to Mexico and Central America, and some individuals also spend the season in the West Indies, Cuba, and northern South America.
Additional Maps
Identification
The Black-throated Green Warbler is characterized by its bright yellow face, olive cheeks, crown, and back, with a prominent long tail extending beyond the undertail coverts. It displays dark streaks on white flanks and a yellow wash on the vent in all plumages. Only breeding males possess a solid black throat, while also having a black chin and upper breast, a yellow face, and white streaked belly. Adult females and juveniles share similarities with males but are less vibrant and their throats are not as black.
The Black-throated Green Warbler is a highly active and agile bird that primarily hunts for small insects hidden in the lower parts of tall tree leaves. These warblers move through tree canopies by hopping and flying between trees, usually staying within the canopy. During migration and winter, they often join mixed flocks with other bird species. Breeding males display their heads while singing from perches. When defending their territory, male warblers can be quite aggressive; the victorious male might perform a moth-like flight. Male Black-throated Green Warblers sing two distinct songs for territorial interactions and attracting females: an unaccented high-pitched buzz, zee zee zo zo zee, and an accented variation, zee zee zee zee zo zee. Their common hoarse double chip call and high clear “see” call are notable during flight.
Habitat
The Black-throated Green Warbler nests in various forest types, such as conifer forests in the northwest, mixed hardwood forests in the southern Appalachians, and cypress swamps along the mid-Atlantic coast. They thrive in boreal coniferous forests and transitional zones between coniferous and deciduous habitats, and have exhibited adaptability to mixed and deciduous forests, even extending into purely deciduous environments in some regions. During breeding, the species prefers coniferous and mixed forests, with a particular affinity for spruce, white pine, hemlock, red cedar, and jack pine. Throughout its life cycle, this species prefers woody habitats, including both deciduous and coniferous woodland areas.
In migration, the warbler is commonly found in woodland and edge habitats. For wintering, it predominantly occupies montane regions in Central America, favoring tall forest canopies.
Conservation Status
- Listed as Least Concern by the International Union for Conservation of Nature (IUCN)
- Listed as Species of Greatest Conservation Need by the 2015 Delaware Wildlife Action Plan (pg 46)
- Listed as Species of Greatest Conservation Need by the 2015 Massachusetts Wildlife Action Plan (pg 172)
- Listed as Secure by Nature Serve Explorer
- Listed as Species of Greatest Conservation Need by the 2015-2025 Pennsylvania Wildlife Action Plan (pg 408)
Threats to Conservation
The primary conservation challenge facing the Black-throated Green Warbler is the degradation and loss of its habitat. Despite their wide breeding range, these warblers are more prevalent within forest interiors rather than edges, leaving them susceptible to habitat fragmentation. Deforestation on their tropical wintering grounds also reduces suitable habitat. Additionally, the species is further impacted by invasive insects, such as the hemlock wooly adelgid and balsam wooly adelgid, which have caused extensive conifer mortality across certain regions resulting in local population declines. The spread of these pests has led to significant declines and even local disappearances of the Black-throated Green Warbler in affected areas, notably in northeastern U.S. and the southern Appalachians.