BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Osprey In Sierra Nevada

All regionsSierra NevadaGeneralists

Osprey in Sierra Nevada has increased: up 48% on the route-weighted index since 1975.

+48%Since 1975TrendPercent 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 →
19Routes 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 →
47YearsYears 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 →

No notable trend signals for Osprey in Sierra Nevada. See the full index history below.

Osprey In Sierra Nevada Population Forecast

If the recent trend holds, Osprey in Sierra Nevada is projected to fall about 16% by 2029 — from 0.42 in 2024 to a central estimate of 0.35 (95% range 0.12–0.59). A 5-year backtest shows a typical error of ±45.6%, with 100% of held-out values landing inside the 95% band.

-16%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 →
0.35Projected 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 →
0.12–0.5995% 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 →
±45.6%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 Sierra Nevada is projected to fall about 16% by 2029 — from 0.42 in 2024 to a central estimate of 0.35 (95% range 0.12–0.59). A 5-year backtest shows a typical error of ±45.6%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.340.100.58
20260.340.110.58
20270.350.110.58
20280.350.110.59
20290.350.120.59

Routes In Sierra Nevada

Routes recording Osprey in Sierra Nevada.
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 →
Bass LakeCALIFORNIA32018
GeneseeCALIFORNIA32024
ChilcootCALIFORNIA32009
WestvilleCALIFORNIA22017
JohnsvilleCALIFORNIA22015
Higgins CornCALIFORNIA22011
LakeshoreCALIFORNIA22024
ChesterCALIFORNIA22016
Meadow ValleyCALIFORNIA22024
Eagle LakeCALIFORNIA12023
DardanelleCALIFORNIA12014
SattleyCALIFORNIA12016
Butte MeadowCALIFORNIA12013
RivertonCALIFORNIA12019
PaxtonCALIFORNIA12024
Little TruckeeCALIFORNIA12013
Pollock PinesCALIFORNIA12017
WawonaCALIFORNIA12009
StrawberryCALIFORNIA12018

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