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

Nashville Warbler In Northern Rockies

All regionsNorthern RockiesForest birds

Nashville Warbler in Northern Rockies has surged: up 194% on the route-weighted index since 1970.

+194%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 →
76Routes 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 →

Nashville Warbler has surged in Northern Rockies: up 194% on the route-weighted index since 1970.

Nashville Warbler In Northern Rockies Population Forecast

If the recent trend holds, Nashville Warbler in Northern Rockies is projected to rise about 106% by 2030 — from 0.34 in 2025 to a central estimate of 0.69 (95% range 0.36–1.0). A 5-year backtest shows a typical error of ±37.9%, with 80% of held-out values landing inside the 95% band.

+106%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 →
0.69Projected 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 →
0.36–1.095% 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 →
±37.9%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, Nashville Warbler in Northern Rockies is projected to rise about 106% by 2030 — from 0.34 in 2025 to a central estimate of 0.69 (95% range 0.36–1.0). A 5-year backtest shows a typical error of ±37.9%, with 80% 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 →
20260.660.320.99
20270.660.331.00
20280.670.341.0
20290.680.351.0
20300.690.361.0

Routes In Northern Rockies

Routes recording Nashville 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 →
Sullivan LkWASHINGTON161999
Sullivan Lake 2WASHINGTON102025
Lolo PassIDAHO82019
SunbeamIDAHO81994
Omak CreekWASHINGTON82024
ArleeMONTANA62025
Fish CreekMONTANA62024
Twin LakesWASHINGTON62024
CurlewWASHINGTON62013
LaurierWASHINGTON52025
St RegisMONTANA42025
NinemileMONTANA42025
NoxonMONTANA42023
KellerWASHINGTON42007
ChewelahWASHINGTON42021
CusickWASHINGTON42025
L Pend O NwrWASHINGTON42024
Rochat DivdeIDAHO32023
Libby DamMONTANA32024
Threemile WaMONTANA32025
OchocoOREGON32024
NaplesIDAHO22025
NezperceIDAHO22012
GrangevilleIDAHO21995
GoldenIDAHO22016

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