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

Hermit Warbler Population Trend in Oregon

All statesForest birds

Hermit Warbler in Oregon has increased: up 41% on the route-weighted index since 1970.

+41%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 →
59Routes 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 Hermit 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 →

No notable trend signals for Hermit Warbler in Oregon. See the full index history below.

Hermit Warbler Population Forecast in Oregon

If the recent trend holds, Hermit Warbler in Oregon is projected to rise about 89% by 2030 — from 3.5 in 2025 to a central estimate of 6.6 (95% range 3.5–9.6). A 5-year backtest shows a typical error of ±51.8%, with 60% of held-out values landing inside the 95% band.

+89%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 →
6.6Projected 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 →
3.5–9.695% 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 →
±51.8%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, Hermit Warbler in Oregon is projected to rise about 89% by 2030 — from 3.5 in 2025 to a central estimate of 6.6 (95% range 3.5–9.6). A 5-year backtest shows a typical error of ±51.8%, with 60% 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 →
20266.43.39.4
20276.43.49.5
20286.53.49.5
20296.53.59.6
20306.63.59.6

Hermit Warbler Survey Routes in Oregon

Routes recording Hermit 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 →
Fisher7820101997
Klickitat Mt6119961993
Blue River5120251992
Trask Summit4720241992
Cinderella3920251993
Hazel Camp3620221975
Cool Camp3420131968
Fisher 22820252017
Selma2620251993
Harlan 22520252011
Molalla2420251994
Mt Hood2020251972
Warner Mtn.2020251992
Harlan1820092006
Ruch1820251992
Secret Val1420251975
Shellrock1320241968
Lobster Creek1220252025
Timber1120171974
Waldport1120011992
Myrtle Grove1020241992
Nicolai Mtn.920251993
Bull Run920252007
Sams Valley820251993
Days Creek720251971

Hermit Warbler Population Trend in Other States

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