BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

Hermit Warbler In Great Basin

All regionsGreat BasinForest birds

Hermit Warbler in Great Basin has edged up: up 22% on the route-weighted index since 1973.

+22%Since 1973TrendPercent 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 →
24Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Great Basin. See the full index history below.

Hermit Warbler In Great Basin Population Forecast

If the recent trend holds, Hermit Warbler in Great Basin is projected to stay roughly flat through 2030, near 0.42 (95% range 0.19–0.66). A 5-year backtest shows a typical error of ±37%, with 100% of held-out values landing inside the 95% band.

+1%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 →
0.42Projected 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 →
0.19–0.6695% 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 →
±37%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 Great Basin is projected to stay roughly flat through 2030, near 0.42 (95% range 0.19–0.66). A 5-year backtest shows a typical error of ±37%, with 100% of held-out values landing inside the 95% band.19712030
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 →
20260.410.170.65
20270.410.180.65
20280.420.180.66
20290.420.180.66
20300.420.190.66

Routes In Great Basin

Routes recording Hermit Warbler in Great Basin.
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 →
E. Mt. AdamsWASHINGTON282025
Mt HoodOREGON202025
Suiattle RivWASHINGTON152019
Camp ShermanOREGON61996
Crowder FlatCALIFORNIA32019
Badger CreekOREGON32025
L. WenatcheeWASHINGTON32025
TionestaCALIFORNIA22021
Medicine Mtn.CALIFORNIA22015
Dell SpringOREGON21989
Davis LakeOREGON22024
RonaldWASHINGTON21997
MacdoelCALIFORNIA12019
Clear Lk ResCALIFORNIA11996
BartleCALIFORNIA12021
HackamoreCALIFORNIA12007
Lapham Res.OREGON12001
Wizard FallsOREGON12023
Bald Mtn.OREGON12009
SistersOREGON12004
RimrockWASHINGTON11976
SnowdenWASHINGTON12025
White ChuckWASHINGTON11999
CarltonWASHINGTON11998

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