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

Cliff Swallow In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Cliff Swallow in Coastal California has edged down: down 14% on the route-weighted index since 1970.

-14%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 →
116Routes 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 →
56YearsYears 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.

Forecast

If the recent trend holds, Cliff Swallow in Coastal California is projected to fall about 24% by 2029 — from 84 in 2024 to a central estimate of 64 (95% range 17–112). A 5-year backtest shows a typical error of ±49.7%, with 100% of held-out values landing inside the 95% band.

-24%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 →
64Projected 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 →
17–11295% 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 →
±49.7%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 24% by 2029 — from 84 in 2024 to a central estimate of 64 (95% range 17–112). A 5-year backtest shows a typical error of ±49.7%, 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 →
20256821116
20266720115
20276619114
20286518113
20296417112

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 →
HughsonCALIFORNIA6312024
Ora LomaCALIFORNIA6012024
PenningtonCALIFORNIA4842024
ShafterCALIFORNIA3901989
ZamoraCALIFORNIA3062024
AthloneCALIFORNIA2952007
Staten Is.CALIFORNIA2422024
SangerCALIFORNIA2272024
Buena VistaCALIFORNIA2212019
WestleyCALIFORNIA2072024
OrlandCALIFORNIA1952017
AuburnCALIFORNIA1591980
LivermoreCALIFORNIA1331991
Jofegan 2CALIFORNIA1332024
RumseyCALIFORNIA1252008
CordovaCALIFORNIA1231981
Red BluffCALIFORNIA1212024
TracyCALIFORNIA1212009
GravesboroCALIFORNIA1181995
Cp. PendletonCALIFORNIA1182004
BakersfieldCALIFORNIA1132023
TranquillityCALIFORNIA1082024
HollisterCALIFORNIA1022011
GlennCALIFORNIA992023
CoyoteCALIFORNIA952024

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