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

Blue Grosbeak Population Trend in Arizona

All statesForest birds

Blue Grosbeak in Arizona has risen sharply: up 72% on the route-weighted index since 1970.

+72%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 →
45Routes 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 Blue 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 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 →

Blue Grosbeak has risen sharply in Arizona: up 72% on the route-weighted index since 1970.

Blue Grosbeak Population Forecast in Arizona

If the recent trend holds, Blue Grosbeak in Arizona is projected to fall about 18% by 2030 — from 2.4 in 2025 to a central estimate of 1.9 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±24.3%, with 100% of held-out values landing inside the 95% band.

-18%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 →
1.9Projected 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 →
0.00–4.495% 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 →
±24.3%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, Blue Grosbeak in Arizona is projected to fall about 18% by 2030 — from 2.4 in 2025 to a central estimate of 1.9 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±24.3%, 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 →
20262.00.004.5
20272.00.004.5
20282.00.004.4
20292.00.004.4
20301.90.004.4

Blue Grosbeak Survey Routes in Arizona

Routes recording Blue 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 →
Pomerene4220251968
Tsaile3719951995
Sunizona 21720252001
Mcneal1220251992
Portal820251977
Hunt519901968
Patagonia520251968
Sunizona519971968
Amado520251993
Rucker420091993
Dateland420161999
Peña Blanca420241975
Cutter 2420182015
Skull Valley320241996
Sahuarita320241993
Peach Spring320251998
Seligman320211992
Carr Mtn320221985
Dragoon220091993
Skull Valley 2220252025
Cibola Lake220021993
Black Mesa119951990
Oraibi120181994
Prescott120251974
Mormon Lake119741974

Blue Grosbeak Population Trend in Other States

alabamaarkansascaliforniacoloradodelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandminnesotamississippimissourimontananebraskanevadanew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvirginiawest-virginiawyoming

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