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Species · Washington · BBS 2026 Release · 1966–2025

Nashville Warbler Population Trend in Washington

All statesForest birds

Nashville Warbler in Washington has surged: up 761% on the route-weighted index since 1970.

+761%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 →
54Routes In StateSurvey 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 Nashville Warbler Trends in WashingtonNotable 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 Washington: up 761% on the route-weighted index since 1970.

Nashville Warbler Population Forecast in Washington

If the recent trend holds, Nashville Warbler in Washington is projected to rise about 122% by 2030 — from 1.9 in 2025 to a central estimate of 4.1 (95% range 2.9–5.3). A 5-year backtest shows a typical error of ±47%, with 80% of held-out values landing inside the 95% band.

+122%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 →
4.1Projected 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 →
2.9–5.395% 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 →
±47%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 Washington is projected to rise about 122% by 2030 — from 1.9 in 2025 to a central estimate of 4.1 (95% range 2.9–5.3). A 5-year backtest shows a typical error of ±47%, 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 →
20263.92.75.1
20273.92.75.1
20284.02.85.2
20294.02.85.3
20304.12.95.3

Nashville Warbler Survey Routes in Washington

Routes recording Nashville Warbler in Washington.
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. Adams1720251995
Sullivan Lk1619991999
Snowden1520251971
Leavenworth1420241981
Sullivan Lake 21020252000
L. Wenatchee920251993
Ronald820251973
Omak Creek820241996
Rimrock720251981
Mazama720221993
Mt. Adams720251994
Twisp620241969
Twin Lakes620241984
Curlew620131993
Laurier520252000
Keller420071968
Chewelah420211977
L Pend O Nwr420241995
Cusick420251982
Lake Chelan420251988
Newhalem320241971
Ardenvoir319871983
Cougar320231983
Kendall320161984
Winthrop320191983

Nashville Warbler Population Trend in Other States

californiaconnecticutidahomainemarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-dakotaoregonpennsylvaniarhode-islandvermontvirginiawest-virginiawisconsin

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