Black-throated Green Warbler
Black-throated Green Warbler
Setophaga virens
At a Glance
In the east, some of the easiest warbler voices to recognize are the patterned songs of the Black-throated Green. As if to confirm the identification, the brilliantly colored male often perches out in the open to sing, perhaps on a high twig of a spruce. He actually has two song types, used in different situations: he sings zoo zee zoo zoo zee to proclaim and defend his nesting territory, and zee zee zee zoo zee in courtship or when communicating with his mate.
All bird guide text and rangemaps adapted from Lives of North American Birds by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Perching Birds, Wood Warblers
IUCN Status
Least Concern
Habitat
Forests and Woodlands, Shrublands, Savannas, and Thickets
Region
California, Eastern Canada, Florida, Great Lakes, Mid Atlantic, New England, Plains, Rocky Mountains, Southeast, Southwest, Texas, Western Canada
Behavior
Direct Flight, Flitter
Population
9.200.000
Range & Identification
Migration & Range Maps
Migrates mostly at night. Fall passage may last fairly late, extending well into October, even in the North.
Description
5" (13 cm). Yellow face contrasts with black throat, bright moss green back and crown. Obvious white wing-bars. Female and young have black on throat partly replaced by white.
Size
About the size of a Sparrow
Color
Black, Green, White, Yellow
Wing Shape
Rounded
Tail Shape
Notched, Square-tipped
Songs and Calls
Thin, buzzy, lazy zeer, zeer, zeer, zeer, zee? or faster zee-zee-zee-zoo-zee.
Call Pattern
Flat, Rising
Call Type
Buzz, Chirp/Chip, Hi, Whistle
Habitat
Mainly conifers. Breeds mostly in coniferous and mixed forests, very locally in deciduous forest. Often nests around spruce, also in white pine, hemlock, red cedar, and jack pine. An isolated race on the southern Atlantic Coast breeds in cypress swamps. During migration, occurs widely in woodland and edges. Usually winters in foothills and mountains among oaks and pines.
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Behavior
Eggs
4, sometimes 3-5. Gray to creamy white with spots or scrawls of reddish brown. Only female incubates, 12 days. In some areas, up to one-third of nests are parasitized by cowbirds.
Young
Nestlings are fed only by female at first, later by male. Young leave nest 11 days after hatching. Parents split up the fledglings, each adult tending half the brood for up to 1 month.
Feeding Behavior
Searches for insects among branches, twigs, and bases of leaves, moving rapidly between foraging sites. Frequently hovers to take insects from underside of leaves. Occasionally catches insects in mid-air. Males tend to forage higher than females while breeding. In late summer, often forages in mixed flocks with chickadees.
Diet
Insects, especially caterpillars. Feeds mainly on non-hairy caterpillars during summer, as well as beetles, true bugs, gnats, aphids, and others, also spiders. Takes poison ivy berries and other berries in migration. In winter, may eat protein corpuscles of tropical cecropia trees.
Nesting
Males establish territories by singing, also by chasing and fighting with intruding males. Nest sites are next to trunk where two or more small branches fork out of conifer, usually low (often only a few feet above ground). The race nesting in southern swamps places its nest well out from trunk, and often higher (to 50' or more above ground). Nest (built by both sexes) is open cup of twigs, grass, weeds, bark, spiderwebs, lined with plant fibers, hair, moss, and feathers.
Conservation
Conservation Status
Has declined as a nesting bird in parts of the northeast during recent decades. Elsewhere, still widespread and common.
Climate Threats Facing the Black-throated Green Warbler
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.