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

Bank Swallow In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Bank Swallow in Coastal California has collapsed: down 95% on the route-weighted index since 1972.

-95%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 →
11Routes 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 →
32YearsYears 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 →

Bank Swallow has collapsed in Coastal California: down 95% on the route-weighted index since 1972.

Bank Swallow In Coastal California Population Forecast

If the recent trend holds, Bank Swallow in Coastal California is projected to stay roughly flat through 2026, near 0.46 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±4980.1%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2026TrendPercent 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 →
0.46Projected 2026 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–2.395% 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 →
±4980.1%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, Bank Swallow in Coastal California is projected to stay roughly flat through 2026, near 0.46 (95% range 0.00–2.3). A 5-year backtest shows a typical error of ±4980.1%, with 100% of held-out values landing inside the 95% band.19702026
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 →
20220.510.002.4
20230.490.002.4
20240.480.002.4
20250.470.002.4
20260.460.002.3

Routes In Coastal California

Routes recording Bank 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 →
GlennCALIFORNIA1101997
JacksonCALIFORNIA311979
OrlandCALIFORNIA101992
AuburnCALIFORNIA41974
HughsonCALIFORNIA31984
ParkfieldCALIFORNIA21977
AdelaidaCALIFORNIA21978
Elizabeth LkCALIFORNIA21970
Red BluffCALIFORNIA12021
PenningtonCALIFORNIA11991
GreenfieldCALIFORNIA12015

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