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Species · Washington · BBS 2026 Release · 1966–2025

Black-throated Gray Warbler Population Trend in Washington

All statesForest birds

Black-throated Gray Warbler in Washington has declined: down 42% on the route-weighted index since 1970.

-42%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 →
55Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

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

No notable trend signals for Black-throated Gray Warbler in Washington. See the full index history below.

Black-throated Gray Warbler Population Forecast in Washington

If the recent trend holds, Black-throated Gray Warbler in Washington is projected to stay roughly flat through 2030, near 1.9 (95% range 0.11–3.7). A 5-year backtest shows a typical error of ±35.8%, with 80% of held-out values landing inside the 95% band.

+8%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 →
1.9Projected 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 →
0.11–3.795% 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 →
±35.8%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 in Washington is projected to stay roughly flat through 2030, near 1.9 (95% range 0.11–3.7). A 5-year backtest shows a typical error of ±35.8%, with 80% 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 →
20262.00.183.8
20271.90.163.7
20281.90.143.7
20291.90.133.7
20301.90.113.7

Black-throated Gray Warbler Survey Routes in Washington

Routes recording Black-throated Gray Warbler in Washington.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Cougar3320231969
Montesand2720241989
Index2019711968
Raymond 21820242022
Newhalem1720251968
Kendall1420251981
Neilton1319751975
Mt. Adams1120242002
Glacier1020241977
White Chuck1020251992
Raymond920211993
Cedar Falls820141993
Ozette720251973
Concrete720252013
Suiattle Riv620181993
Kamilche520251968
South Elma520241975
Warm Beach320071968
Cascade Riv320061989
Mendota 2320001989
Bunker Hill320251968
Mcchord320141997
Mendota319881977
Pe Ell320251993
Carnation320241988

Black-throated Gray Warbler Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.