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

Northern Harrier Population Trend in Oklahoma

All statesGeneralists

Northern Harrier in Oklahoma has collapsed: down 94% on the route-weighted index since 1969.

-94%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 →
36Routes 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Harrier Trends in OklahomaNotable 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 declinecomputed 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 →

Northern Harrier has collapsed in Oklahoma: down 94% on the route-weighted index since 1969.

Northern Harrier Population Forecast in Oklahoma

If the recent trend holds, Northern Harrier in Oklahoma is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±300.1%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.3395% 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 →
±300.1%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, Northern Harrier in Oklahoma is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.33). A 5-year backtest shows a typical error of ±300.1%, with 100% 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 →
20250.000.000.33
20260.000.000.33
20270.000.000.33
20280.000.000.33
20290.000.000.33

Northern Harrier Survey Routes in Oklahoma

Routes recording Northern Harrier in Oklahoma.
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 →
Arapaho419921992
Rosston319671967
Ft Sill East219941994
Beggs220121967
Eagle City219951971
Douglas220131968
Beaver220132007
Woodward220082008
Hooker220171993
Keyes220171993
Duncan220061994
Phillips119731973
Mill Creek119691969
Loco119761969
Randlett119741967
Cookietown119681968
Reed119981998
Indianola119821967
Noble119751975
Verden119701970
Grimes119941967
Erick119851969
Peoria119841969
Welch120241967
Collinsville119931967

Northern Harrier Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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