BirdAnalyst
Species · Arizona · BBS 2025 Release · 1966–2024

Blue Grosbeak Population Trend in Arizona

All statesGeneralists

Blue Grosbeak in Arizona has risen sharply: up 65% on the route-weighted index since 1970.

+65%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 →
44Routes 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 →
56YearsYears 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 65% 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 39% by 2029 — from 3.2 in 2024 to a central estimate of 1.9 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±25.3%, with 100% of held-out values landing inside the 95% band.

-39%Change by 2029TrendPercent 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 2029 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 →
±25.3%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 39% by 2029 — from 3.2 in 2024 to a central estimate of 1.9 (95% range 0.00–4.4). A 5-year backtest shows a typical error of ±25.3%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20252.00.004.5
20262.00.004.5
20272.00.004.5
20282.00.004.4
20291.90.004.4

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 →
Pomerene5720241968
Tsaile3719951995
Amado1720231993
Patagonia1420241968
Sunizona 21220242001
Portal1020241977
Redington1020231993
Mcneal620241992
Hunt519901968
Sunizona519971968
Rucker420091993
Prescott420221974
Dateland420161999
Peña Blanca420241975
Cutter 2420182015
Peach Spring420221998
Skull Valley320241996
Sahuarita320241993
Seligman320211992
Carr Mtn320221985
Dragoon220091993
Cibola Lake220021993
Black Mesa119951990
Oraibi120181994
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 2026-05-22.