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

American Dipper Population Trend in Montana

All statesGeneralists

American Dipper in Montana has edged down: down 12% on the route-weighted index since 1975.

-12%Since 1975TrendPercent 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 →
24Routes 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 →
50YearsYears 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 MontanaNotable 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 Montana. See the full index history below.

American Dipper Population Forecast in Montana

If the recent trend holds, American Dipper in Montana is projected to fall about 76% by 2029 — from 0.09 in 2024 to a central estimate of 0.02 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±117.5%, with 100% of held-out values landing inside the 95% band.

-76%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 →
0.02Projected 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 →
0.00–0.1295% 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 →
±117.5%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, American Dipper in Montana is projected to fall about 76% by 2029 — from 0.09 in 2024 to a central estimate of 0.02 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±117.5%, with 100% of held-out values landing inside the 95% band.19732029
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 →
20250.030.000.13
20260.030.000.13
20270.030.000.12
20280.030.000.12
20290.020.000.12

American Dipper Survey Routes in Montana

Routes recording American Dipper in Montana.
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 →
Sula319771977
St Regis220241977
Clinton220241978
Libby Dam119881981
Logan Pass120171980
Threemile Wa119981993
Arlee120071973
Woodman120171976
Elliston119821974
Inside Road119981998
Chestnut120231976
Red Rock120081973
Swan Lake120242022
Greenoagh 2120082008
Thompson Riv120122000
Ninemile120241993
Philipsburg120242023
Clancy120222022
Fish Creek120111996
Skalkaho119981992
Hebgen Lake120232021
Painted Rock120181995
Wise River120242019
Noxon120171995

American Dipper Population Trend in Other States

alaskacaliforniacoloradoidahonevadanew-mexicooregonsouth-dakotautahwashingtonwyoming

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