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

Gray Hawk Population Trend in Arizona

All statesGeneralists

Gray Hawk in Arizona has surged: up 653% on the route-weighted index since 1970.

+653%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 →
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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Gray Hawk 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 →

Gray Hawk has surged in Arizona: up 653% on the route-weighted index since 1970.

Gray Hawk Population Forecast in Arizona

If the recent trend holds, Gray Hawk in Arizona is projected to fall about 20% by 2029 — from 0.60 in 2024 to a central estimate of 0.48 (95% range 0.22–0.74). A 5-year backtest shows a typical error of ±38.4%, with 60% of held-out values landing inside the 95% band.

-20%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 →
0.48Projected 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 →
0.22–0.7495% 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 →
±38.4%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, Gray Hawk in Arizona is projected to fall about 20% by 2029 — from 0.60 in 2024 to a central estimate of 0.48 (95% range 0.22–0.74). A 5-year backtest shows a typical error of ±38.4%, with 60% 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 →
20250.440.180.70
20260.450.190.71
20270.460.200.72
20280.470.210.73
20290.480.220.74

Gray Hawk Survey Routes in Arizona

Routes recording Gray Hawk 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 →
Pomerene920241997
Patagonia620241968
Amado620231993
Redington520231993
Peña Blanca520242005
Sunizona 2320232013
Skull Valley120242024
Portal120232023
Sahuarita120232023

Gray Hawk Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.