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Species · Alaska · BBS 2026 Release · 1966–2025

Townsend's Warbler Population Trend in Alaska

All statesForest birds

Townsend's Warbler in Alaska has surged: up 115% on the route-weighted index since 1982.

+115%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 →
45YearsYears 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 115% 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 rise about 15% by 2030 — from 5.2 in 2025 to a central estimate of 5.9 (95% range 3.3–8.6). A 5-year backtest shows a typical error of ±18.6%, with 80% of held-out values landing inside the 95% band.

+15%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 →
5.9Projected 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 →
3.3–8.695% 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 →
±18.6%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 rise about 15% by 2030 — from 5.2 in 2025 to a central estimate of 5.9 (95% range 3.3–8.6). A 5-year backtest shows a typical error of ±18.6%, with 80% of held-out values landing inside the 95% band.19722030
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 →
20265.73.18.4
20275.83.18.4
20285.83.28.5
20295.93.28.5
20305.93.38.6

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 →
Whale Pass8120241997
Thorne Bay 27920252013
Craig7320251983
Thorne Bay5520121989
Ketchikan5120221972
Chichagof Is5120241994
Kuiu Island4620102004
Chena Hot Spring 24020251999
Moose Pass3719921983
Seward3519921982
Hoonah3020241993
Homer2519821982
Sitka2520241993
Haines2020251991
Mitkof Isle2020251988
Zimovia Strt2020251990
Kenai Lake (Short)1719921984
Petersburg1619871987
Zarembo1520241998
Hyder1320091994
Hope1220251985
Birch Lake820251993
Sitka (Short)819921984
Juneau Alt619861984
Anchor River620251983

Townsend's Warbler Population Trend in Other States

idahomontanaoregonwashingtonwyoming

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