BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Townsend's Warbler In Northern Rockies

All regionsNorthern RockiesForest birds

Townsend's Warbler in Northern Rockies has surged: up 219% on the route-weighted index since 1970.

+219%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 →
93Routes 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 →

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 Northern Rockies: up 219% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Townsend's Warbler in Northern Rockies is projected to rise about 90% by 2029 — from 3.5 in 2024 to a central estimate of 6.6 (95% range 4.8–8.4). A 5-year backtest shows a typical error of ±54%, with 20% of held-out values landing inside the 95% band.

+90%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 →
6.6Projected 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 →
4.8–8.495% 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 →
±54%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 Northern Rockies is projected to rise about 90% by 2029 — from 3.5 in 2024 to a central estimate of 6.6 (95% range 4.8–8.4). A 5-year backtest shows a typical error of ±54%, with 20% 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 →
20256.34.48.1
20266.44.58.2
20276.44.68.3
20286.54.78.4
20296.64.88.4

Routes In Northern Rockies

Routes recording Townsend's Warbler in Northern Rockies.
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 →
Lolo PassIDAHO1622019
Baldy MountainIDAHO512016
St RegisMONTANA512024
MivodenIDAHO492023
Marble CreekIDAHO472023
Whitefish LakeMONTANA382024
AveryIDAHO362023
Fish CreekMONTANA352024
Eagle CreekOREGON302022
Black Mtn.OREGON292004
Hash RockOREGON252024
Nezperce NfIDAHO241999
N Fork Cda RIDAHO232019
NewbridgeOREGON222024
GoldenIDAHO212016
PierceIDAHO212007
Rochat DivdeIDAHO212023
CusickWASHINGTON212024
L Pend O NwrWASHINGTON212024
CoolinIDAHO202024
OchocoOREGON182024
Sullivan LkWASHINGTON181999
Sullivan Lake 2WASHINGTON182024
OchocoOREGON171982
WoodmanMONTANA162024

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