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

American Dipper Population Trend in Alaska

All statesGeneralists

American Dipper in Alaska has collapsed: down 84% on the route-weighted index since 1984.

-84%Since 1984TrendPercent 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 →
22Routes 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 →
31YearsYears 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 AlaskaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

American Dipper has collapsed in Alaska: down 84% on the route-weighted index since 1984.

American Dipper Population Forecast in Alaska

If the recent trend holds, American Dipper in Alaska is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±167.1%, 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 →
0.00Projected 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 →
0.00–0.1095% 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 →
±167.1%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 Alaska is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.10). A 5-year backtest shows a typical error of ±167.1%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.000.000.10
20260.000.000.10
20270.000.000.10
20280.000.000.10
20290.000.000.10

American Dipper Survey Routes in Alaska

Routes recording American Dipper in Alaska.
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 →
Hyder220012001
Thorne Bay 2220182016
Chatanika R120222022
Chiniak119881985
Nabesna Road119901990
Cantwell120182006
Chena Hot Spring 2120101999
Juneau Alt119841984
Juneau120211986
Council120172017
Haines120221975
Kodiak119831983
Cordova120171983
Togiak River119991999
Dillingham120012001
Chichagof Is120241998
Sitka (Short)119861986
Kanektok Riv120012000
Cold Bay120232000
Harlequin L.120042004
Kodiak 2119941991
Hatcher Pass120231999

American Dipper Population Trend in Other States

californiacoloradoidahomontananevadanew-mexicooregonsouth-dakotautahwashingtonwyoming

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