BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Townsend's Warbler In Northern Rockies

All regionsNorthern RockiesForest birds

Townsend's Warbler in Northern Rockies has surged: up 207% on the route-weighted index since 1970.

+207%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 →
95Routes 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 →
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 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 207% on the route-weighted index since 1970.

Townsend's Warbler In Northern Rockies Population Forecast

If the recent trend holds, Townsend's Warbler in Northern Rockies is projected to rise about 88% by 2030 — from 3.5 in 2025 to a central estimate of 6.5 (95% range 4.5–8.4). A 5-year backtest shows a typical error of ±72.8%, with 0% of held-out values landing inside the 95% band.

+88%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 →
6.5Projected 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 →
4.5–8.495% 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 →
±72.8%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, Townsend's Warbler in Northern Rockies is projected to rise about 88% by 2030 — from 3.5 in 2025 to a central estimate of 6.5 (95% range 4.5–8.4). A 5-year backtest shows a typical error of ±72.8%, with 0% 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 →
20266.24.28.1
20276.24.38.2
20286.34.48.3
20296.44.58.3
20306.54.58.4

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
St RegisMONTANA632025
Baldy MountainIDAHO512016
AveryIDAHO402025
Whitefish LakeMONTANA382024
Marble CreekIDAHO352025
Fish CreekMONTANA352024
MivodenIDAHO292025
Black Mtn.OREGON292004
WoodmanMONTANA262025
Nezperce NfIDAHO241999
N Fork Cda RIDAHO232019
GoldenIDAHO212016
PierceIDAHO212007
Sullivan Lake 2WASHINGTON212025
L Pend O NwrWASHINGTON212024
OchocoOREGON192025
NinemileMONTANA182025
NewbridgeOREGON182025
DesolationOREGON182025
Sullivan LkWASHINGTON181999
OchocoOREGON171982
Hash RockOREGON162025
BarnhouseOREGON152025
Rochat DivdeIDAHO142025

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