BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

Northern Harrier Population Trend in North Dakota

All statesBirds of prey

Northern Harrier in North Dakota has edged down: down 22% on the route-weighted index since 1969.

-22%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 →
50Routes 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 →
58YearsYears 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 North DakotaNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Northern Harrier in North Dakota. See the full index history below.

Northern Harrier Population Forecast in North Dakota

If the recent trend holds, Northern Harrier in North Dakota is projected to rise about 50% by 2030 — from 1.2 in 2025 to a central estimate of 1.8 (95% range 0.89–2.7). A 5-year backtest shows a typical error of ±54%, with 80% of held-out values landing inside the 95% band.

+50%Change by 2030TrendPercent 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 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.89–2.795% 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 →
±54%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 North Dakota is projected to rise about 50% by 2030 — from 1.2 in 2025 to a central estimate of 1.8 (95% range 0.89–2.7). A 5-year backtest shows a typical error of ±54%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20261.80.882.7
20271.80.882.7
20281.80.892.7
20291.80.892.7
20301.80.892.7

Northern Harrier Survey Routes in North Dakota

Routes recording Northern Harrier in North 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 →
Niles620251992
Bowesmont520141969
Solen520242005
Buchanan420251969
Webster420241991
Carson420241988
Kempton320171968
Denbigh320251968
Lark319861969
Zap320241967
Sheyenne Lk320251987
Danzig 2320232019
Forman220241973
Edgeley220251982
Emerado220251973
Cooperstown220251972
Horsehead Lk220241980
Rolla220241969
Regan220251968
Loraine220191982
Tobacco220181968
Roosevelt Pk220191983
Parshall220131982
Montpelier220251990
Bowesmont 2220162015

Northern Harrier Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.