BirdAnalyst
Species · BCR 15 · BBS 2025 Release · 1966–2024

Spotted Towhee In Sierra Nevada

All regionsSierra NevadaGeneralists

Spotted Towhee in Sierra Nevada has surged: up 91% on the route-weighted index since 1970.

+91%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 →
39Routes 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 →

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 →

Spotted Towhee has surged in Sierra Nevada: up 91% on the route-weighted index since 1970.

Spotted Towhee In Sierra Nevada Population Forecast

If the recent trend holds, Spotted Towhee in Sierra Nevada is projected to rise about 21% by 2029 — from 15 in 2024 to a central estimate of 18 (95% range 13–23). A 5-year backtest shows a typical error of ±18.2%, with 80% of held-out values landing inside the 95% band.

+21%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 →
18Projected 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 →
13–2395% 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 →
±18.2%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, Spotted Towhee in Sierra Nevada is projected to rise about 21% by 2029 — from 15 in 2024 to a central estimate of 18 (95% range 13–23). A 5-year backtest shows a typical error of ±18.2%, with 80% 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 →
2025181223
2026181323
2027181323
2028181323
2029181323

Routes In Sierra Nevada

Routes recording Spotted Towhee 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 →
CoultervilleCALIFORNIA472019
Forest HillCALIFORNIA342022
Bass LakeCALIFORNIA322019
Eagle LakeCALIFORNIA292024
Tahoe NfCALIFORNIA281994
JohnsvilleCALIFORNIA262024
Silver CityCALIFORNIA262013
KernvilleCALIFORNIA242008
Tuolumne GroveCALIFORNIA232024
Greenhorn MtCALIFORNIA222008
Higgins CornCALIFORNIA222024
WawonaCALIFORNIA222024
PlacervilleCALIFORNIA202024
Kings CanyonCALIFORNIA192024
ChilcootCALIFORNIA192024
GeneseeCALIFORNIA172024
DownievilleCALIFORNIA162024
WestvilleCALIFORNIA152024
PaxtonCALIFORNIA152024
Forest Hill 2CALIFORNIA152005
Cottage SpgsCALIFORNIA131975
LakeshoreCALIFORNIA132024
StrawberryCALIFORNIA122019
Hat CreekCALIFORNIA112018
RivertonCALIFORNIA102023

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