BirdAnalyst
Species · BCR 32 · BBS 2026 Release · 1966–2025

Cliff Swallow In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Cliff Swallow in Coastal California has held roughly steady: up 9% on the route-weighted index since 1970.

+9%Since 1970TrendPercent 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 →
117Routes 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 →
57YearsYears 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 Cliff Swallow in Coastal California. See the full index history below.

Cliff Swallow In Coastal California Population Forecast

If the recent trend holds, Cliff Swallow in Coastal California is projected to fall about 28% by 2030 — from 90 in 2025 to a central estimate of 65 (95% range 18–112). A 5-year backtest shows a typical error of ±41.2%, with 100% of held-out values landing inside the 95% band.

-28%Change by 2030TrendPercent 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 →
65Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
18–11295% 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 →
±41.2%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, Cliff Swallow in Coastal California is projected to fall about 28% by 2030 — from 90 in 2025 to a central estimate of 65 (95% range 18–112). A 5-year backtest shows a typical error of ±41.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20266921116
20276821115
20286720114
20296619113
20306518112

Routes In Coastal California

Routes recording Cliff Swallow 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 →
Ora LomaCALIFORNIA6472025
WestleyCALIFORNIA5792025
HughsonCALIFORNIA4452025
ShafterCALIFORNIA3901989
PenningtonCALIFORNIA3092025
AthloneCALIFORNIA2952007
ZamoraCALIFORNIA2502025
SangerCALIFORNIA2272024
Staten Is.CALIFORNIA2272025
Buena VistaCALIFORNIA2212019
OrlandCALIFORNIA1952017
AuburnCALIFORNIA1591980
LivermoreCALIFORNIA1331991
RumseyCALIFORNIA1252008
CordovaCALIFORNIA1231981
TracyCALIFORNIA1212009
GravesboroCALIFORNIA1181995
Cp. PendletonCALIFORNIA1182004
BakersfieldCALIFORNIA1132023
Lake BerryessaCALIFORNIA1082025
TranquillityCALIFORNIA1082024
CoyoteCALIFORNIA1062025
HollisterCALIFORNIA1022011
Jofegan 2CALIFORNIA982025
Yolla BollyCALIFORNIA952025

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