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

Townsend's Warbler Population Trend in Oregon

All statesForest birds

Townsend's Warbler in Oregon has surged: up 98% on the route-weighted index since 1970.

+98%Since 1970TrendPercent 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 →
65Routes 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 →
57YearsYears 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 OregonNotable 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 Oregon: up 98% on the route-weighted index since 1970.

Townsend's Warbler Population Forecast in Oregon

If the recent trend holds, Townsend's Warbler in Oregon is projected to stay roughly flat through 2030, near 2.0 (95% range 0.89–3.0). A 5-year backtest shows a typical error of ±26.1%, with 100% of held-out values landing inside the 95% band.

+9%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 →
2.0Projected 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 →
0.89–3.095% 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 →
±26.1%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, Townsend's Warbler in Oregon is projected to stay roughly flat through 2030, near 2.0 (95% range 0.89–3.0). A 5-year backtest shows a typical error of ±26.1%, 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 →
20261.90.823.0
20271.90.843.0
20281.90.863.0
20291.90.883.0
20302.00.893.0

Townsend's Warbler Survey Routes in Oregon

Routes recording Townsend's Warbler in Oregon.
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 →
Black Mtn.2920041995
Shellrock2420241969
Ochoco1920251993
Newbridge1820251993
Desolation1820251993
Ochoco1719821972
Hash Rock1620251983
Barnhouse1520251998
Granite1220251986
Hells Canyon1120251992
Monument1120251993
Wickiup1020251969
Eagle Creek1020251993
Flora820231986
Svensen819901990
Summit Pr720251984
Emigrant Lake 2520192009
Troy520251992
Ruch520252025
Albee420251968
Mount Vernon420241986
Elk Lake420251972
Fisher 2420252018
Cool Camp320091968
Scappoose320232023

Townsend's Warbler Population Trend in Other States

alaskaidahomontanawashingtonwyoming

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