BirdAnalyst
Species · BBS 2026 Release · 1966–2025

Black-throated Gray Warbler Population Analysis

ParulidaeForest birdsSetophaga nigrescens

Black-throated Gray Warbler has surged: up 117% on the route-weighted index since 1970.

+117%Since 1970TrendPercent 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 →
446RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57Years 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 Gray Warbler

The Black-throated Gray Warbler (Setophaga nigrescens) 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 446 Breeding Bird Survey routes across 10 states, most concentrated in the Northern Pacific Rainforest.
Family
Parulidae · Forest birds

Notable Black-throated Gray 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 Gray Warbler has surged in surveyed states: up 117% on the route-weighted index since 1970.

Black-throated Gray Warbler Population Forecast

If the recent trend holds, Black-throated Gray Warbler is projected to rise about 42% by 2030 — from 0.26 in 2025 to a central estimate of 0.36 (95% range 0.25–0.48). A 5-year backtest shows a typical error of ±43.3%, with 20% of held-out values landing inside the 95% band.

+42%Change by 2030TrendPercent 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 →
0.36Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.25–0.4895% 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 →
±43.3%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 Gray Warbler is projected to rise about 42% by 2030 — from 0.26 in 2025 to a central estimate of 0.36 (95% range 0.25–0.48). A 5-year backtest shows a typical error of ±43.3%, with 20% of held-out values landing inside the 95% band.19682030
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 →
20260.360.240.47
20270.360.250.47
20280.360.250.47
20290.360.250.48
20300.360.250.48

Where the Black-throated Gray Warbler Is Detected

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

Black-throated Gray Warbler Population Trend by State

Black-throated Gray 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 →
Arizona+71%197031
California+101%1970135
Colorado+206%197540
Idaho-12%19867
Nevada-39%199215
New Mexico-1%197023
Oregon-4%197076
Utah-6%197760
Washington-42%197055
Wyominginsufficient datan/a4

Black-throated Gray Warbler Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Black-throated Gray 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 →
Northern Pacific Rainforest-34%1970125
Great Basin-8%197079
Northern Rockies-39%199018
Sierra Nevada+257%197130
Southern Rockies / Colorado Plateau-1%1970109
Coastal California+875%197051
Sierra Madre Occidental+63%197426
Chihuahuan Desert-4%19893

Black-throated Gray Warbler Conservation Status

Our route-weighted index shows it up about 117% since 1970.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.