BirdAnalyst
Species · BCR 19 · BBS 2025 Release · 1966–2024

Northern Harrier In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieGeneralists

Northern Harrier in Central Mixed Grass Prairie has collapsed: down 96% on the route-weighted index since 1969.

-96%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 →
77Routes 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 →
54YearsYears 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 →

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 Central Mixed Grass Prairie: down 96% on the route-weighted index since 1969.

Forecast

If the recent trend holds, Northern Harrier in Central Mixed Grass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±233.7%, 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 →
0.00–0.2495% 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 →
±233.7%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 Central Mixed Grass Prairie is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.24). A 5-year backtest shows a typical error of ±233.7%, 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 →
20250.000.000.24
20260.000.000.24
20270.000.000.24
20280.000.000.24
20290.000.000.24

Routes In Central Mixed Grass Prairie

Routes recording Northern Harrier in Central Mixed Grass Prairie.
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 →
HaysKANSAS52008
RexfordKANSAS42007
ArapahoOKLAHOMA41992
CovertKANSAS32004
HopewellKANSAS32011
HolbrookNEBRASKA32019
SurpriseNEBRASKA32007
TableNEBRASKA31981
RosstonOKLAHOMA31967
AshlandKANSAS22005
AlbertKANSAS21997
LeovilleKANSAS22012
Eagle CityOKLAHOMA21995
DouglasOKLAHOMA22013
BeaverOKLAHOMA22013
WoodwardOKLAHOMA22008
Ft Sill EastOKLAHOMA21994
DaltonKANSAS12000
St JohnKANSAS11987
CoatsKANSAS11967
ColdwaterKANSAS12004
BuckeyeKANSAS12002
KanopolisKANSAS12018
GrayKANSAS11997
HollenbergKANSAS11993

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