BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Nashville Warbler In Sierra Nevada

All regionsSierra NevadaForest birds

Nashville Warbler in Sierra Nevada has risen sharply: up 62% on the route-weighted index since 1973.

+62%Since 1973TrendPercent 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 →
35Routes 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 →
53YearsYears 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 risen sharply in Sierra Nevada: up 62% on the route-weighted index since 1973.

Forecast

If the recent trend holds, Nashville Warbler in Sierra Nevada is projected to rise about 36% by 2029 — from 7.7 in 2024 to a central estimate of 10 (95% range 6.8–14). A 5-year backtest shows a typical error of ±18.3%, with 100% of held-out values landing inside the 95% band.

+36%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 →
10Projected 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 →
6.8–1495% 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 →
±18.3%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 Sierra Nevada is projected to rise about 36% by 2029 — from 7.7 in 2024 to a central estimate of 10 (95% range 6.8–14). A 5-year backtest shows a typical error of ±18.3%, with 100% of held-out values landing inside the 95% band.19712029
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 →
2025106.614
2026106.614
2027106.714
2028106.814
2029106.814

Routes In Sierra Nevada

Routes recording Nashville Warbler in Sierra Nevada.
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 →
JohnsvilleCALIFORNIA382024
PlacervilleCALIFORNIA342024
Forest Hill 2CALIFORNIA342005
Bass LakeCALIFORNIA322011
DownievilleCALIFORNIA252024
Forest HillCALIFORNIA242022
RivertonCALIFORNIA192023
Tahoe NfCALIFORNIA171994
Hat CreekCALIFORNIA162018
Tuolumne GroveCALIFORNIA122024
Butte MeadowCALIFORNIA122014
WawonaCALIFORNIA122024
Eagle LakeCALIFORNIA92022
Greenhorn MtCALIFORNIA72008
LumberyardCALIFORNIA62024
Lassen ParkCALIFORNIA51981
WestvilleCALIFORNIA52024
DardanelleCALIFORNIA42019
GeneseeCALIFORNIA42024
LakeshoreCALIFORNIA42024
Little TruckeeCALIFORNIA42023
Silver CityCALIFORNIA32013
Kings CanyonCALIFORNIA32011
PaxtonCALIFORNIA32024
StrawberryCALIFORNIA32019

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