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Species · Washington · BBS 2026 Release · 1966–2025

Evening Grosbeak Population Trend in Washington

All statesForest birds

Evening Grosbeak in Washington has fallen sharply: down 74% on the route-weighted index since 1970.

-74%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 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 Evening Grosbeak 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 declinecomputed 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 →

Evening Grosbeak has fallen sharply in Washington: down 74% on the route-weighted index since 1970.

Evening Grosbeak Population Forecast in Washington

If the recent trend holds, Evening Grosbeak in Washington is projected to stay roughly flat through 2030, near 2.1 (95% range 0.00–8.8). A 5-year backtest shows a typical error of ±55.8%, with 100% of held-out values landing inside the 95% band.

+8%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 →
2.1Projected 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 →
0.00–8.895% 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 →
±55.8%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, Evening Grosbeak in Washington is projected to stay roughly flat through 2030, near 2.1 (95% range 0.00–8.8). A 5-year backtest shows a typical error of ±55.8%, with 100% 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 →
20262.40.009.1
20272.30.009.0
20282.20.009.0
20292.20.008.9
20302.10.008.8

Evening Grosbeak Survey Routes in Washington

Routes recording Evening Grosbeak 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 →
Omak Creek2920221996
Winthrop2820091985
L. Wenatchee2120251993
Neilton1319751975
E. Mt. Adams1220251995
Ronald1220251973
Raymond 2820242023
Mt Rainier820151991
Mendota 2720002000
Deer Park720011994
Snowden620251982
Cusick620241984
Carlton620131992
Nighthawk620131992
Greenwater620252015
Kamilche520251968
Rimrock520251968
Curlew520181993
Blewett Pass520251992
Mt. Adams520251993
Newhalem420251968
Kendall420241981
Packwood420241976
Chewelah320191977
Ardenvoir319871969

Evening Grosbeak Population Trend in Other States

arizonacaliforniacoloradoconnecticutidahomainemassachusettsmichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonsouth-dakotautahvermontwisconsinwyoming

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