BirdAnalyst
Species · Idaho · BBS 2026 Release · 1966–2025

American Dipper Population Trend in Idaho

All statesWetland birds

American Dipper in Idaho has held roughly steady: up 10% on the route-weighted index since 1975.

+10%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 IdahoNotable 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 Idaho. See the full index history below.

American Dipper Population Forecast in Idaho

If the recent trend holds, American Dipper in Idaho is projected to fall about 23% by 2030 — from 0.26 in 2025 to a central estimate of 0.20 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±51.2%, with 100% of held-out values landing inside the 95% band.

-23%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 →
0.20Projected 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 →
0.00–0.4495% 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 →
±51.2%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 Idaho is projected to fall about 23% by 2030 — from 0.26 in 2025 to a central estimate of 0.20 (95% range 0.00–0.44). A 5-year backtest shows a typical error of ±51.2%, with 100% 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 →
20260.200.000.44
20270.200.000.44
20280.200.000.44
20290.200.000.44
20300.200.000.44

American Dipper Survey Routes in Idaho

Routes recording American Dipper in Idaho.
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 →
N Fork Cda R520191993
Centerville520251982
Avery220251980
Rochat Divde220091994
Marble Creek220231988
Cobalt220132009
Naples120021976
Nezperce119971969
Lolo Pass120012001
Golden120151987
Cascade119751975
Cape Horn119941994
Challis120121983
Squirrel120021986
Alturas119681968
Magic Mtn120141989
Henry119811981
Sawtooth City 2120252022
Pierce120071990
Burgdorf120161989
Yellow Pine120151990
Sunbeam120251994
Featherville120111990
Nezperce Nf119991999

American Dipper Population Trend in Other States

alaskacaliforniacoloradomontananevadanew-mexicooregonsouth-dakotautahwashingtonwyoming

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