BirdAnalyst
Species · BCR 15 · BBS 2026 Release · 1966–2025

Barn Swallow In Sierra Nevada

All regionsSierra NevadaAerial insectivores

Barn Swallow in Sierra Nevada has fallen sharply: down 73% on the route-weighted index since 1970.

-73%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 →
25Routes 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 →

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 →

Barn Swallow has fallen sharply in Sierra Nevada: down 73% on the route-weighted index since 1970.

Barn Swallow In Sierra Nevada Population Forecast

If the recent trend holds, Barn Swallow in Sierra Nevada is projected to stay roughly flat through 2030, near 0.67 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±132.4%, with 100% of held-out values landing inside the 95% band.

+0%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 →
0.67Projected 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 →
0.00–2.195% 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 →
±132.4%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, Barn Swallow in Sierra Nevada is projected to stay roughly flat through 2030, near 0.67 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±132.4%, 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 →
20260.800.002.3
20270.770.002.2
20280.730.002.2
20290.700.002.2
20300.670.002.1

Routes In Sierra Nevada

Routes recording Barn Swallow in Sierra Nevada.
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 →
Cottage SpgsCALIFORNIA81975
Forest Hill 2CALIFORNIA82005
GeneseeCALIFORNIA62024
PaxtonCALIFORNIA62025
Meadow ValleyCALIFORNIA62023
SattleyCALIFORNIA42025
Butte MeadowCALIFORNIA42000
Tuolumne GroveCALIFORNIA31984
DownievilleCALIFORNIA32019
Forest HillCALIFORNIA32019
Eagle LakeCALIFORNIA21979
WestvilleCALIFORNIA21986
Bass LakeCALIFORNIA22008
LakeshoreCALIFORNIA22014
PlacervilleCALIFORNIA22019
WawonaCALIFORNIA22011
ChilcootCALIFORNIA22009
JohnsvilleCALIFORNIA12011
WoodfordsCALIFORNIA12025
Silver CityCALIFORNIA11994
Higgins CornCALIFORNIA12014
RivertonCALIFORNIA12025
GoumazCALIFORNIA12005
StrawberryCALIFORNIA11999
Last ChanceCALIFORNIA12011

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