BirdAnalyst
Species · BCR 4 · BBS 2026 Release · 1966–2025

Osprey In BCR 4

All regionsBCR 4Birds of prey

Osprey in BCR 4 has surged: up 283% on the route-weighted index since 1996.

+283%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 →
17Routes 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 →
30YearsYears 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 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 →

Osprey has surged in BCR 4: up 283% on the route-weighted index since 1996.

Osprey In BCR 4 Population Forecast

If the recent trend holds, Osprey in BCR 4 is projected to fall about 48% by 2029 — from 0.42 in 2024 to a central estimate of 0.22 (95% range 0.09–0.36). A 5-year backtest shows a typical error of ±46.4%, with 60% of held-out values landing inside the 95% band.

-48%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 →
0.22Projected 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 →
0.09–0.3695% 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 →
±46.4%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, Osprey in BCR 4 is projected to fall about 48% by 2029 — from 0.42 in 2024 to a central estimate of 0.22 (95% range 0.09–0.36). A 5-year backtest shows a typical error of ±46.4%, with 60% of held-out values landing inside the 95% band.19872029
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 →
20250.200.070.34
20260.210.070.34
20270.210.080.35
20280.220.080.35
20290.220.090.36

Routes In BCR 4

Routes recording Osprey in BCR 4.
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 →
Mud RiverALASKA52024
Kanuti LakeALASKA52024
Birch LakeALASKA22023
Burma RoadALASKA22011
Unalakleet RiverALASKA22024
Hather CreekALASKA22024
Anvik RiverALASKA22024
NorthwayALASKA12018
WillowALASKA12018
Lake LouiseALASKA12003
Nicholai SlALASKA12008
PetersvilleALASKA11987
Seven LakesALASKA12024
ColdfootALASKA12022
Kanuti CanynALASKA12023
Porcupine R.ALASKA12001
Kobuk River (Short)ALASKA11991

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