BirdAnalyst
Species · South Dakota · BBS 2025 Release · 1966–2024

Ferruginous Hawk Population Trend in South Dakota

All statesGeneralists

Ferruginous Hawk in South Dakota has surged: up 616% on the route-weighted index since 1973.

+616%Since 1973TrendPercent 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 →
32Routes 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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ferruginous Hawk Trends in South DakotaNotable 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 →

Ferruginous Hawk has surged in South Dakota: up 616% on the route-weighted index since 1973.

Ferruginous Hawk Population Forecast in South Dakota

If the recent trend holds, Ferruginous Hawk in South Dakota is projected to fall about 62% by 2029 — from 0.55 in 2024 to a central estimate of 0.21 (95% range 0.01–0.41). A 5-year backtest shows a typical error of ±103.4%, with 80% of held-out values landing inside the 95% band.

-62%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 →
0.21Projected 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 →
0.01–0.4195% 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 →
±103.4%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, Ferruginous Hawk in South Dakota is projected to fall about 62% by 2029 — from 0.55 in 2024 to a central estimate of 0.21 (95% range 0.01–0.41). A 5-year backtest shows a typical error of ±103.4%, with 80% of held-out values landing inside the 95% band.19692029
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 →
20250.200.000.41
20260.200.000.41
20270.210.000.41
20280.210.000.41
20290.210.010.41

Ferruginous Hawk Survey Routes in South Dakota

Routes recording Ferruginous Hawk in South Dakota.
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 →
Indian520241998
Reva420241996
Crow Creek320102009
Gettysburg320001992
Cottonwood220171994
S. Pioneer220242008
Long Lake220131977
Gorman219801980
Isabel220152009
Pioneer120211992
Geddes119971997
Rockyford120232016
Roswell119811981
Railroad Butte120172017
Ft Thompson120071970
French Creek119961995
Forbes119861982
Promise120111996
Owanka120022002
Volunteer119881979
Ottumwa120041969
Harding120171973
Cedar Pass119781977
Fort Pierre119951980
Maurine120221980

Ferruginous Hawk Population Trend in Other States

arizonacaliforniacoloradoidahokansasmontananebraskanevadanew-mexiconorth-dakotaoklahomaoregontexasutahwashingtonwyoming

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