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Species · Alaska · BBS 2025 Release · 1966–2024

Townsend's Warbler Population Trend in Alaska

All statesForest birds

Townsend's Warbler in Alaska has surged: up 131% on the route-weighted index since 1982.

+131%Since 1982TrendPercent 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 →
72Routes 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 Townsend's Warbler 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 increasecomputed 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 →

Townsend's Warbler has surged in Alaska: up 131% on the route-weighted index since 1982.

Townsend's Warbler Population Forecast in Alaska

If the recent trend holds, Townsend's Warbler in Alaska is projected to fall about 32% by 2029 — from 8.8 in 2024 to a central estimate of 6.0 (95% range 3.2–8.7). A 5-year backtest shows a typical error of ±21.6%, with 80% of held-out values landing inside the 95% band.

-32%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 →
6.0Projected 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 →
3.2–8.795% 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 →
±21.6%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, Townsend's Warbler in Alaska is projected to fall about 32% by 2029 — from 8.8 in 2024 to a central estimate of 6.0 (95% range 3.2–8.7). A 5-year backtest shows a typical error of ±21.6%, with 80% of held-out values landing inside the 95% band.19722029
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 →
20255.83.18.5
20265.83.18.6
20275.93.28.6
20285.93.28.7
20296.03.28.7

Townsend's Warbler Survey Routes in Alaska

Routes recording Townsend's Warbler 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 →
Thorne Bay 29420242013
Whale Pass8120241997
Craig7920241983
Chena Hot Spring 25920241999
Thorne Bay5520121989
Ketchikan5120221972
Chichagof Is5120241994
Kuiu Island4620102004
Mitkof Isle3820241988
Haines3720241991
Moose Pass3719921983
Seward3519921982
Hoonah3020241993
Zimovia Strt2920241990
Homer2519821982
Sitka2520241993
Kenai Lake (Short)1719921984
Petersburg1619871987
Zarembo1520241998
Hope1520241985
Hyder1320091994
Juneau1020241983
Sitka (Short)819921984
Juneau Alt619861984
Beaver Creek519771977

Townsend's Warbler Population Trend in Other States

idahomontanaoregonwashingtonwyoming

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