BirdAnalyst
Species · New York · BBS 2025 Release · 1966–2024

Northern Harrier Population Trend in New York

All statesGeneralists

Northern Harrier in New York has surged: up 113% on the route-weighted index since 1969.

+113%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 →
57Routes 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 →
55YearsYears 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 New YorkNotable 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 increasecomputed 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 surged in New York: up 113% on the route-weighted index since 1969.

Northern Harrier Population Forecast in New York

If the recent trend holds, Northern Harrier in New York is projected to fall about 25% by 2028 — from 0.10 in 2023 to a central estimate of 0.07 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±38.5%, with 100% of held-out values landing inside the 95% band.

-25%Change by 2028TrendPercent 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 →
0.07Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1895% 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 →
±38.5%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 New York is projected to fall about 25% by 2028 — from 0.10 in 2023 to a central estimate of 0.07 (95% range 0.00–0.18). A 5-year backtest shows a typical error of ±38.5%, with 100% of held-out values landing inside the 95% band.19672028
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 →
20240.070.000.18
20250.070.000.18
20260.070.000.18
20270.070.000.18
20280.070.000.18

Northern Harrier Survey Routes in New York

Routes recording Northern Harrier in New York.
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 →
Gainesville319971967
Swain 2220232014
Dryden220221984
Randolph220081978
Centerville219911972
Alder Creek219981970
Number Four220081987
Waddington219911983
Westhampton119961992
Huntington120112011
Oxford 2120031979
Austerlitz120012001
Cooperstown119691969
Meridale119951995
Duanesburg120141989
Oneonta119691969
Oriskany Fls119951967
Oxford119741967
Romulus120001991
Macdougall119891971
Trumansburg120002000
Vestal Ctr120131977
Phillips Cr120131969
Swain120021974
Orleans119851983

Northern Harrier Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradodelawaregeorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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