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

American Barn Owl In Coastal California

All regionsCoastal CaliforniaGeneralists

American Barn Owl in Coastal California has fallen sharply: down 52% on the route-weighted index since 1972.

-52%Since 1972TrendPercent 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 →
48Routes 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 →
43YearsYears 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 →

American Barn Owl has fallen sharply in Coastal California: down 52% on the route-weighted index since 1972.

American Barn Owl In Coastal California Population Forecast

If the recent trend holds, American Barn Owl in Coastal California is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±48.6%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.04Projected 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 →
0.00–0.1295% 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 →
±48.6%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, American Barn Owl in Coastal California is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.12). A 5-year backtest shows a typical error of ±48.6%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.040.000.12
20260.040.000.12
20270.040.000.12
20280.040.000.12
20290.040.000.12

Routes In Coastal California

Routes recording American Barn Owl 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 →
MoragaCALIFORNIA42005
AdelaidaCALIFORNIA22021
WestleyCALIFORNIA21977
OnealsCALIFORNIA22016
LivermoreCALIFORNIA21979
TracyCALIFORNIA22004
Tracy 2CALIFORNIA22017
Red BluffCALIFORNIA11977
PenningtonCALIFORNIA11990
RumseyCALIFORNIA11975
RiovistaCALIFORNIA12011
CollegevilleCALIFORNIA11998
HughsonCALIFORNIA12023
Tres PinosCALIFORNIA11981
GravesboroCALIFORNIA11986
ParkfieldCALIFORNIA11975
BakersfieldCALIFORNIA11999
Santa YnezCALIFORNIA11994
Oak GroveCALIFORNIA12018
San YsidroCALIFORNIA11989
HollisterCALIFORNIA12011
Orange CoveCALIFORNIA11993
Lake SuccessCALIFORNIA11980
Morro BayCALIFORNIA11993
Point ReyesCALIFORNIA12012

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