BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Black-throated Green Warbler

ParulidaeForest birdsSetophaga virens

Black-throated Green Warbler has surged: up 115% on the route-weighted index since 1968.

+115%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
734RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Black-throated Green Warbler

The Black-throated Green Warbler (Setophaga virens) is a North American member of the Wood-Warblers (Parulidae). In this analysis it is grouped with the forest birds.

Size
4.5–5.5 in long (11–14 cm) — a small, active songbird (typical for the family)
Habitat
Woodlands and forest edges, including wooded suburbs and parks.
Diet
Insects and spiders gleaned from foliage and bark, with seeds and berries in season.
Range
Recorded on 734 Breeding Bird Survey routes across 26 states, most concentrated in the Appalachian Mountains.
Family
Parulidae · Forest birds

Notable Black-throated Green Warbler TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Black-throated Green Warbler has surged in surveyed states: up 115% on the route-weighted index since 1968.

Black-throated Green Warbler Population Forecast

If the recent trend holds, Black-throated Green Warbler is projected to rise about 44% by 2029 — from 0.62 in 2024 to a central estimate of 0.90 (95% range 0.68–1.1). A 5-year backtest shows a typical error of ±42.5%, with 0% of held-out values landing inside the 95% band.

+44%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.90Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.68–1.195% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±42.5%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Black-throated Green Warbler is projected to rise about 44% by 2029 — from 0.62 in 2024 to a central estimate of 0.90 (95% range 0.68–1.1). A 5-year backtest shows a typical error of ±42.5%, with 0% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.860.641.1
20260.870.651.1
20270.880.661.1
20280.890.671.1
20290.900.681.1

Where the Black-throated Green Warbler Is Detected

BBS routes recording Black-throated Green Warbler, sized by most recent count.

Black-throated Green Warbler Population Trend by State

Black-throated Green Warbler population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Alabama-16%196816
Arkansas+950%199410
Connecticut-29%197118
Georgia+532%19796
Indiana+321%19915
Kentucky+90%19806
Maine+38%196878
Maryland17×196813
Massachusetts+32%196924
Michigan+470%196870
Minnesota+353%196934
Missouriinsufficient datan/a2
New Hampshire+159%196826
New Jersey-46%19795
New York+25%1968100
North Carolina+511%197230
Ohio+499%197418
Oklahomainsufficient datan/a2
Pennsylvania24×1968100
Rhode Island-69%19695
South Carolinainsufficient datan/a2
Tennessee+623%196817
Vermont+238%196826
Virginia+751%196829
West Virginia+381%196847
Wisconsin+93%196845

Black-throated Green Warbler Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Black-throated Green Warbler population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Boreal Hardwood Transition+110%1968117
Lower Great Lakes / St. Lawrence Plain+80%196854
Atlantic Northern Forest+139%1968155
Prairie Hardwood Transition+335%197534
Central Hardwoods+493%19918
West Gulf Coastal Plain / Ouachitas+544%20068
Southeastern Coastal Plain-77%197416
Appalachian Mountains+490%1968281
Piedmont-49%19869
New England / Mid-Atlantic Coast-25%196850

Black-throated Green Warbler Conservation Status

Our route-weighted index shows it up about 115% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.