BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Osprey In Coastal California

All regionsCoastal CaliforniaGeneralists

Osprey in Coastal California has surged: up 816% on the route-weighted index since 1976.

+816%Since 1976TrendPercent 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 →
34Routes 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 →

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 Coastal California: up 816% on the route-weighted index since 1976.

Osprey In Coastal California Population Forecast

If the recent trend holds, Osprey in Coastal California is projected to stay roughly flat through 2029, near 0.42 (95% range 0.22–0.62). A 5-year backtest shows a typical error of ±123.8%, with 40% of held-out values landing inside the 95% band.

+3%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 →
0.42Projected 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 →
0.22–0.6295% 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 →
±123.8%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 Coastal California is projected to stay roughly flat through 2029, near 0.42 (95% range 0.22–0.62). A 5-year backtest shows a typical error of ±123.8%, with 40% 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 →
20250.390.190.59
20260.400.200.59
20270.400.200.60
20280.410.210.61
20290.420.220.62

Routes In Coastal California

Routes recording Osprey in Coastal California.
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 →
HughsonCALIFORNIA52024
OrovilleCALIFORNIA42024
CopperopolisCALIFORNIA42024
PenningtonCALIFORNIA22024
Morro BayCALIFORNIA21973
Point ReyesCALIFORNIA22022
Lake BerryessaCALIFORNIA22024
ArvinCALIFORNIA22015
ReddingCALIFORNIA21976
Glen Ellen 2CALIFORNIA22012
Harbor Lake 2CALIFORNIA22018
Red BluffCALIFORNIA12024
RumseyCALIFORNIA12008
Foster ParkCALIFORNIA11980
CoalingaCALIFORNIA11996
Orange CoveCALIFORNIA12016
FairfaxCALIFORNIA12019
OnoCALIFORNIA12006
FolsomCALIFORNIA12021
Sawmill MtnCALIFORNIA12013
GlennCALIFORNIA12019
TehamaCALIFORNIA11993
MoragaCALIFORNIA12016
Yolla BollyCALIFORNIA11996
Bartlett SpsCALIFORNIA12018

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