BirdAnalyst
Species · BCR 4 · BBS 2025 Release · 1966–2024

Osprey In BCR 4

All regionsBCR 4Generalists

Osprey in BCR 4 has surged: up 291% on the route-weighted index since 1996.

+291%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 →
16Routes 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 291% 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 49% by 2029 — from 0.44 in 2024 to a central estimate of 0.23 (95% range 0.09–0.37). A 5-year backtest shows a typical error of ±46.8%, with 60% of held-out values landing inside the 95% band.

-49%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 →
0.23Projected 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 →
0.09–0.3795% 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 →
±46.8%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 49% by 2029 — from 0.44 in 2024 to a central estimate of 0.23 (95% range 0.09–0.37). A 5-year backtest shows a typical error of ±46.8%, 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
20260.210.070.35
20270.210.080.35
20280.220.080.36
20290.230.090.37

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
ColdfootALASKA12022
Kanuti CanynALASKA12023
Porcupine R.ALASKA12001
Kobuk River (Short)ALASKA11991

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