BirdAnalyst
Species · BCR 2 · BBS 2025 Release · 1966–2024

Northern Harrier In BCR 2

All regionsBCR 2Generalists

Northern Harrier in BCR 2 has fallen sharply: down 61% on the route-weighted index since 1996.

-61%Since 1996TrendPercent 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 →
13Routes 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 →
20YearsYears 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 fallen sharply in BCR 2: down 61% on the route-weighted index since 1996.

Forecast

If the recent trend holds, Northern Harrier in BCR 2 is projected to stay roughly flat through 2029, near 0.12 (95% range 0.00–0.35). A 5-year backtest shows a typical error of ±72.9%, with 80% of held-out values landing inside the 95% band.

+9%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 →
0.12Projected 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 →
0.00–0.3595% 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 →
±72.9%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 BCR 2 is projected to stay roughly flat through 2029, near 0.12 (95% range 0.00–0.35). A 5-year backtest shows a typical error of ±72.9%, with 80% of held-out values landing inside the 95% band.19862029
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 →
20250.130.000.36
20260.130.000.36
20270.130.000.36
20280.120.000.35
20290.120.000.35

Routes In BCR 2

Routes recording Northern Harrier in BCR 2.
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 →
Salmon LakeALASKA32017
TellerALASKA22017
King SalmonALASKA12024
Cape NomeALASKA12011
CouncilALASKA12018
NomeALASKA12009
St. Mary'SALASKA12014
Togiak RiverALASKA12001
Gweek RiverALASKA11997
KotzebueALASKA12023
Selawik (Short)ALASKA11986
Kotzebue (Short)ALASKA11986
Cold Bay (Short)ALASKA11990

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