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

Evening Grosbeak Population Trend in Arizona

All statesForest birds

Evening Grosbeak in Arizona has collapsed: down 84% on the route-weighted index since 1987.

-84%Since 1987TrendPercent 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 →
9Routes 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 →
25YearsYears 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 ArizonaNotable 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 collapsed in Arizona: down 84% on the route-weighted index since 1987.

Evening Grosbeak Population Forecast in Arizona

If the recent trend holds, Evening Grosbeak in Arizona is projected to stay roughly flat through 2030, near 0.00 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±101.4%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.2595% 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 →
±101.4%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, Evening Grosbeak in Arizona is projected to stay roughly flat through 2030, near 0.00 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±101.4%, with 100% of held-out values landing inside the 95% band.19852030
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 →
20260.000.000.25
20270.000.000.25
20280.000.000.25
20290.000.000.25
20300.000.000.25

Evening Grosbeak Survey Routes in Arizona

Routes recording Evening Grosbeak in Arizona.
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 →
Pinetop1019931993
Flagstaff319921988
Alpine319931992
Tsaile319961993
Sawmill219961996
Dry Park220251992
Rucker119971997
Blue119911985
Sprucedale119921992

Evening Grosbeak Population Trend in Other States

californiacoloradoconnecticutidahomainemassachusettsmichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonsouth-dakotautahvermontwashingtonwisconsinwyoming

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