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Species · Washington · BBS 2025 Release · 1966–2024

Northern Waterthrush Population Trend in Washington

All statesForest birds

Northern Waterthrush in Washington has increased: up 48% on the route-weighted index since 1989.

+48%Since 1989TrendPercent 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 →
7Routes 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 →
36YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Waterthrush 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 Northern Waterthrush in Washington. See the full index history below.

Northern Waterthrush Population Forecast in Washington

If the recent trend holds, Northern Waterthrush in Washington is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±138%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.05Projected 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 →
0.00–0.1595% 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 →
±138%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, Northern Waterthrush in Washington is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.15). A 5-year backtest shows a typical error of ±138%, with 100% of held-out values landing inside the 95% band.19822029
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 →
20250.050.000.16
20260.050.000.16
20270.050.000.16
20280.050.000.15
20290.050.000.15

Northern Waterthrush Survey Routes in Washington

Routes recording Northern Waterthrush 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 →
Sullivan Lk719991999
Sullivan Lake 2320232001
Cusick220241982
Omak Creek120101996
Northport120071999
L Pend O Nwr120231999
Curlew120131993

Northern Waterthrush Population Trend in Other States

alaskaconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiopennsylvaniarhode-islandvermontvirginiawest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.