BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Townsend's Warbler In Great Basin

All regionsGreat BasinForest birds

Townsend's Warbler in Great Basin has increased: up 27% on the route-weighted index since 1970.

+27%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 →
40Routes 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 →
56YearsYears 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 Townsend's Warbler in Great Basin. See the full index history below.

Townsend's Warbler In Great Basin Population Forecast

If the recent trend holds, Townsend's Warbler in Great Basin is projected to rise about 41% by 2029 — from 1.2 in 2024 to a central estimate of 1.7 (95% range 0.77–2.5). A 5-year backtest shows a typical error of ±28.2%, with 100% of held-out values landing inside the 95% band.

+41%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 →
1.7Projected 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 →
0.77–2.595% 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 →
±28.2%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 Great Basin is projected to rise about 41% by 2029 — from 1.2 in 2024 to a central estimate of 1.7 (95% range 0.77–2.5). A 5-year backtest shows a typical error of ±28.2%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20251.60.742.5
20261.60.752.5
20271.60.762.5
20281.60.772.5
20291.70.772.5

Routes In Great Basin

Routes recording Townsend's 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 →
Blewett PassWASHINGTON872024
RimrockWASHINGTON282024
Index 2WASHINGTON172023
No CascadesWASHINGTON142019
LeavenworthWASHINGTON112024
MazamaWASHINGTON102022
Cascade RivWASHINGTON102006
RonaldWASHINGTON92024
GlacierWASHINGTON82024
SquirrelIDAHO71994
L. WenatcheeWASHINGTON72024
ConcreteWASHINGTON52024
Dell SpringOREGON21999
Davis LakeOREGON22024
Wizard FallsOREGON22024
IndexWASHINGTON21971
SnowdenWASHINGTON22003
WinthropWASHINGTON22022
White ChuckWASHINGTON22024
CarltonWASHINGTON22022
PomeroyWASHINGTON22002
GiffordIDAHO11991
JoelIDAHO12011
PaisleyOREGON12011
Mt HoodOREGON12023

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