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

Red-tailed Hawk Population Trend in Iowa

All statesGeneralists

Red-tailed Hawk in Iowa has surged: up 200% on the route-weighted index since 1969.

+200%Since 1969TrendPercent 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 →
39Routes 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 Red-tailed Hawk Trends in IowaNotable 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 →

Red-tailed Hawk has surged in Iowa: up 200% on the route-weighted index since 1969.

Red-tailed Hawk Population Forecast in Iowa

If the recent trend holds, Red-tailed Hawk in Iowa is projected to rise about 16% by 2029 — from 1.6 in 2024 to a central estimate of 1.8 (95% range 1.2–2.5). A 5-year backtest shows a typical error of ±56.8%, with 60% of held-out values landing inside the 95% band.

+16%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 →
1.8Projected 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 →
1.2–2.595% 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 →
±56.8%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, Red-tailed Hawk in Iowa is projected to rise about 16% by 2029 — from 1.6 in 2024 to a central estimate of 1.8 (95% range 1.2–2.5). A 5-year backtest shows a typical error of ±56.8%, with 60% of held-out values landing inside the 95% band.19672029
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 →
20251.71.12.4
20261.81.12.4
20271.81.22.4
20281.81.22.4
20291.81.22.5

Red-tailed Hawk Survey Routes in Iowa

Routes recording Red-tailed Hawk in Iowa.
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 →
Red Rock420241974
Neola420161969
Scranton420241967
Festina420241971
Hudson320221984
Zearing319951967
Burchinal320241995
Mccallsburg320241998
Mt Hamill220241968
Exline220241974
College Spgs220041970
Bryant220241969
Williamsburg220231967
Alice219991981
Washta220141967
Rock Valley220241973
College Spgs 2220232005
Tipton220231999
Lafayette220242003
Melrose120241976
Bedford120181968
West Liberty120241969
Cedar Valley119961967
Brooklyn120211969
Desmoines119691968

Red-tailed Hawk Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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