Black-throated green warbler

The breeding range of the black-throated green warbler extends from central Canada in the northwest to Newfoundland in the northeast and extends southward along the Appalachian Mountains as far south as northern Georgia. A breeding population also occurs along coastal sections of Virginia to South Carolina. It winters in the West Indies, Central America, and northern South America.

Breeding habitat includes coniferous, mixed, and deciduous forests including forest edges, second growth, and swamps. During the winter, their habitat consists of open forest, woodland, scrub, second growth and thickets.

Black-throated green warblers feed primarily on insects. They generally forage high within the tree canopy.

The breeding season for the black-throated green warbler in New Jersey is between early May to mid-August. They nest in coniferous and hardwood trees, shrubs, and tangles of vines from the ground to about 80 feet off the ground. The nest is constructed primarily by the female. 3 to 5 eggs are laid in May or June and incubation (by the female only) lasts about 12 days. The young are tended to by both parents and leave the nest at 8 to 10 days old.

The black-throated green warbler is listed in New Jersey as a Species of Special Concern (not yet endangered or threatened but possibly on its way). Some survey data indicates a significant population decline within their range. Potential threats are habitat fragmentation and modification within their breeding, migration, and winter ranges as well as nest parasitism by brown-headed cowbirds (Molothrus ater).

Conservation of New Jersey’s warbler species requires long-term monitoring and research, habitat preservation and restoration, reduction in mortality caused by humans, cowbird control, and incentives to promote habitat preservation within their wintering areas.