BirdAnalyst
Species · BCR 11 · BBS 2025 Release · 1966–2024

Northern Harrier In Prairie Potholes

All regionsPrairie PotholesGeneralists

Northern Harrier in Prairie Potholes has held roughly steady: down 6% on the route-weighted index since 1969.

-6%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 →
110Routes In RegionSurvey 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 SignalsNotable 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 Prairie Potholes. See the full index history below.

Forecast

If the recent trend holds, Northern Harrier in Prairie Potholes is projected to rise about 16% by 2029 — from 1.2 in 2024 to a central estimate of 1.3 (95% range 0.74–1.9). A 5-year backtest shows a typical error of ±44.6%, with 80% 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 →
1.3Projected 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 →
0.74–1.995% 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 →
±44.6%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 Prairie Potholes is projected to rise about 16% by 2029 — from 1.2 in 2024 to a central estimate of 1.3 (95% range 0.74–1.9). A 5-year backtest shows a typical error of ±44.6%, with 80% 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 →
20251.30.721.9
20261.30.721.9
20271.30.731.9
20281.30.731.9
20291.30.741.9

Routes In Prairie Potholes

Routes recording Northern Harrier in Prairie Potholes.
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 →
ClevelandMONTANA152024
LambertMONTANA72024
Hay LakeMONTANA62022
Redwood FallMINNESOTA52012
Lake BronsonMINNESOTA52011
SunburstMONTANA52007
ShelbyMONTANA52024
BowesmontNORTH-DAKOTA52014
CondeSOUTH-DAKOTA51984
VirgelleMONTANA42024
Ester LakeMONTANA42024
WebsterNORTH-DAKOTA42024
TenneyMINNESOTA32014
TracyMINNESOTA32013
Big StoneMINNESOTA32012
OswegoMONTANA32024
ChinookMONTANA32024
SacoMONTANA32024
Winside 2NEBRASKA32007
KemptonNORTH-DAKOTA32017
BuchananNORTH-DAKOTA32024
Danzig 2NORTH-DAKOTA32023
Lakota 2NORTH-DAKOTA32024
RaymondSOUTH-DAKOTA32021
LaneSOUTH-DAKOTA31999

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