BirdAnalyst
Species · Wyoming · BBS 2026 Release · 1966–2025

Northern Harrier Population Trend in Wyoming

All statesBirds of prey

Northern Harrier in Wyoming has edged down: down 20% on the route-weighted index since 1970.

-20%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 →
114Routes 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 Northern Harrier Trends in WyomingNotable 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 Wyoming. See the full index history below.

Northern Harrier Population Forecast in Wyoming

If the recent trend holds, Northern Harrier in Wyoming is projected to fall about 15% by 2030 — from 0.39 in 2025 to a central estimate of 0.33 (95% range 0.00–0.76). A 5-year backtest shows a typical error of ±13.2%, with 100% of held-out values landing inside the 95% band.

-15%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 →
0.33Projected 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 →
0.00–0.7695% 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 →
±13.2%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 Wyoming is projected to fall about 15% by 2030 — from 0.39 in 2025 to a central estimate of 0.33 (95% range 0.00–0.76). A 5-year backtest shows a typical error of ±13.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20260.350.000.78
20270.350.000.77
20280.340.000.77
20290.340.000.76
20300.330.000.76

Northern Harrier Survey Routes in Wyoming

Routes recording Northern Harrier in Wyoming.
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 →
Sussex420161992
Daniel419881980
Pathfinder420251983
Shawnee420031991
Reliance420011977
Gvnt Valley420192000
Patrick Draw319781973
Raven320251992
Farson320251995
Green River319841977
Basin220251980
Clarkelen219781968
Natrona219921968
Brookhurst220061968
Savery219891989
Riverside220251990
Frannie220251999
Schoonover220231989
Soda Well220251979
Gebo220241992
Harland Flat220251995
Highlight219821982
Sweetwater220251986
Meadowdale219921992
Lingle220241989

Northern Harrier Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsin

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