BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

American Dipper Population Trend in Washington

All statesGeneralists

American Dipper in Washington has edged down: down 15% on the route-weighted index since 1973.

-15%Since 1973TrendPercent 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 →
33Routes 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 →
44YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable American Dipper 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 American Dipper in Washington. See the full index history below.

American Dipper Population Forecast in Washington

If the recent trend holds, American Dipper in Washington is projected to fall about 44% by 2029 — from 0.09 in 2024 to a central estimate of 0.05 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±99.7%, with 100% 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 →
0.05Projected 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 →
0.00–0.1395% 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 →
±99.7%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, American Dipper in Washington is projected to fall about 44% by 2029 — from 0.09 in 2024 to a central estimate of 0.05 (95% range 0.00–0.13). A 5-year backtest shows a typical error of ±99.7%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.050.000.14
20260.050.000.14
20270.050.000.13
20280.050.000.13
20290.050.000.13

American Dipper Survey Routes in Washington

Routes recording American Dipper 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 →
Twisp219981994
Issaquah219791979
Ronald220241973
Greenwater220192015
Ozette120171976
Port Angeles120241999
Newhalem120111975
Montesand119941992
Cascade Riv119951991
No Cascades120031989
Kamilche120101984
Index119711971
L Pend O Nwr120022002
Bunker Hill120151982
Cougar120132013
Rimrock120141969
Sullivan Lake 2120122012
Kendall120242022
Glacier120111976
Winthrop120071988
Twin Lakes119861986
Cusick120241991
Packwood120131986
White Chuck120221992
Carlton120181996

American Dipper Population Trend in Other States

alaskacaliforniacoloradoidahomontananevadanew-mexicooregonsouth-dakotautahwyoming

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