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

Vesper Sparrow In Sierra Nevada

All regionsSierra NevadaGrassland birds

Vesper Sparrow in Sierra Nevada has held roughly steady: up 2% on the route-weighted index since 1973.

+2%Since 1973TrendPercent 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 →
51YearsYears 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 Vesper Sparrow in Sierra Nevada. See the full index history below.

Vesper Sparrow In Sierra Nevada Population Forecast

If the recent trend holds, Vesper Sparrow in Sierra Nevada is projected to rise about 79% by 2029 — from 0.95 in 2024 to a central estimate of 1.7 (95% range 0.01–3.4). A 5-year backtest shows a typical error of ±236.7%, with 60% of held-out values landing inside the 95% band.

+79%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 →
1.7Projected 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 →
0.01–3.495% 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 →
±236.7%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, Vesper Sparrow in Sierra Nevada is projected to rise about 79% by 2029 — from 0.95 in 2024 to a central estimate of 1.7 (95% range 0.01–3.4). A 5-year backtest shows a typical error of ±236.7%, with 60% of held-out values landing inside the 95% band.19702029
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 →
20251.70.003.4
20261.70.003.4
20271.70.003.4
20281.70.013.4
20291.70.013.4

Routes In Sierra Nevada

Routes recording Vesper Sparrow 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 →
GoumazCALIFORNIA182011
Last ChanceCALIFORNIA172019
SattleyCALIFORNIA152024
Little TruckeeCALIFORNIA92023
WoodfordsCALIFORNIA22017
LakeshoreCALIFORNIA22006
CrestviewCALIFORNIA22024
Eagle LakeCALIFORNIA12022
DardanelleCALIFORNIA12019
RivertonCALIFORNIA11975
ChilcootCALIFORNIA12024

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