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

Nashville Warbler In Great Basin

All regionsGreat BasinForest birds

Nashville Warbler in Great Basin has surged: up 407% on the route-weighted index since 1971.

+407%Since 1971TrendPercent 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 →
63Routes 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 →

Nashville Warbler has surged in Great Basin: up 407% on the route-weighted index since 1971.

Nashville Warbler In Great Basin Population Forecast

If the recent trend holds, Nashville Warbler in Great Basin is projected to rise about 159% by 2030 — from 0.71 in 2025 to a central estimate of 1.8 (95% range 1.3–2.4). A 5-year backtest shows a typical error of ±73.4%, with 20% of held-out values landing inside the 95% band.

+159%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 →
1.8Projected 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 →
1.3–2.495% 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 →
±73.4%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 Great Basin is projected to rise about 159% by 2030 — from 0.71 in 2025 to a central estimate of 1.8 (95% range 1.3–2.4). A 5-year backtest shows a typical error of ±73.4%, with 20% of held-out values landing inside the 95% band.19692030
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 →
20261.71.22.3
20271.81.22.3
20281.81.22.4
20291.81.22.4
20301.81.32.4

Routes In Great Basin

Routes recording Nashville 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. AdamsWASHINGTON172025
SnowdenWASHINGTON152025
LeavenworthWASHINGTON142024
Badger CreekOREGON132025
L. WenatcheeWASHINGTON92025
Mt HoodOREGON82025
RonaldWASHINGTON82025
Camp ShermanOREGON71994
RimrockWASHINGTON72025
MazamaWASHINGTON72022
Wizard FallsOREGON62025
TwispWASHINGTON62024
Lake ChelanWASHINGTON42025
LikelyCALIFORNIA32012
BartleCALIFORNIA32021
NewhalemWASHINGTON32024
ArdenvoirWASHINGTON31987
KendallWASHINGTON32016
WinthropWASHINGTON32019
WilburWASHINGTON32013
NubieberCALIFORNIA22018
Pasadena ValIDAHO21991
ImnahaOREGON21973
Barnes ValOREGON21985
Bly 2OREGON22021

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