BirdAnalyst
Species · California · BBS 2026 Release · 1966–2025

Evening Grosbeak Population Trend in California

All statesForest birds

Evening Grosbeak in California has declined: down 38% on the route-weighted index since 1973.

-38%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 →
62Routes 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 →
54YearsYears 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 CaliforniaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Evening Grosbeak in California. See the full index history below.

Evening Grosbeak Population Forecast in California

If the recent trend holds, Evening Grosbeak in California is projected to rise about 86% by 2030 — from 0.12 in 2025 to a central estimate of 0.22 (95% range 0.00–0.52). A 5-year backtest shows a typical error of ±334.6%, with 100% of held-out values landing inside the 95% band.

+86%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 →
0.22Projected 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 →
0.00–0.5295% 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 →
±334.6%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 California is projected to rise about 86% by 2030 — from 0.12 in 2025 to a central estimate of 0.22 (95% range 0.00–0.52). A 5-year backtest shows a typical error of ±334.6%, with 100% of held-out values landing inside the 95% band.19712030
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 →
20260.230.000.53
20270.230.000.52
20280.220.000.52
20290.220.000.52
20300.220.000.52

Evening Grosbeak Survey Routes in California

Routes recording Evening Grosbeak in California.
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 →
Dorris1420112011
Clear Lk Res1319911991
Goumaz1020091998
Eagle Lake620171983
Macdoel619941978
Bass Lake520082008
Meadow Valley520252008
Little Truckee520251997
Gazelle419891988
Iron Gate319881988
Tionesta320211998
Fall River Mills320072007
Sattley320171989
Medicine Mtn.320212000
Butte Meadow320141972
Lake Success319961978
Riverton320161975
Yreka319981977
Lakeshore320021972
Horse Creek219881988
Ship Mtn.220132012
Whiskeytown220062006
Dirigio220042000
Madeline220182011
Tehama220111974

Evening Grosbeak Population Trend in Other States

arizonacoloradoconnecticutidahomainemassachusettsmichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonsouth-dakotautahvermontwashingtonwisconsinwyoming

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