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

Cassin's Finch In Sierra Nevada

All regionsSierra NevadaForest birds

Cassin's Finch in Sierra Nevada has risen sharply: up 52% on the route-weighted index since 1970.

+52%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 →
33Routes 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 increasecomputed 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 →

Cassin's Finch has risen sharply in Sierra Nevada: up 52% on the route-weighted index since 1970.

Cassin's Finch In Sierra Nevada Population Forecast

If the recent trend holds, Cassin's Finch in Sierra Nevada is projected to stay roughly flat through 2030, near 3.6 (95% range 0.93–6.2). A 5-year backtest shows a typical error of ±74.4%, with 100% of held-out values landing inside the 95% band.

-2%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 →
3.6Projected 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 →
0.93–6.295% 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 →
±74.4%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, Cassin's Finch in Sierra Nevada is projected to stay roughly flat through 2030, near 3.6 (95% range 0.93–6.2). A 5-year backtest shows a typical error of ±74.4%, 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 →
20263.61.06.3
20273.60.986.3
20283.60.976.3
20293.60.956.2
20303.60.936.2

Routes In Sierra Nevada

Routes recording Cassin's Finch 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 →
CrestviewCALIFORNIA232025
Eagle LakeCALIFORNIA132025
ChilcootCALIFORNIA112024
GoumazCALIFORNIA102011
Last ChanceCALIFORNIA102019
Tahoe NfCALIFORNIA91994
DardanelleCALIFORNIA72019
Lassen ParkCALIFORNIA61989
Little TruckeeCALIFORNIA62025
WestvilleCALIFORNIA52025
WoodfordsCALIFORNIA52024
Kings CanyonCALIFORNIA51972
Pine MountainCALIFORNIA52017
DownievilleCALIFORNIA42025
RivertonCALIFORNIA42025
ChesterCALIFORNIA42017
Pollock PinesCALIFORNIA42025
PlacervilleCALIFORNIA41999
JohnsvilleCALIFORNIA32025
Hat CreekCALIFORNIA32018
LakeshoreCALIFORNIA32024
Chaos CraterCALIFORNIA32019
SattleyCALIFORNIA22025
Butte MeadowCALIFORNIA22014
PaxtonCALIFORNIA22010

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