BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Brewer's Sparrow In Great Basin

All regionsGreat BasinGeneralists

Brewer's Sparrow in Great Basin has increased: up 50% on the route-weighted index since 1970.

+50%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 →
217Routes 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 →

No notable trend signals for Brewer's Sparrow in Great Basin. See the full index history below.

Brewer's Sparrow In Great Basin Population Forecast

If the recent trend holds, Brewer's Sparrow in Great Basin is projected to stay roughly flat through 2029, near 16 (95% range 7.3–25). A 5-year backtest shows a typical error of ±36.3%, with 100% of held-out values landing inside the 95% band.

+8%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 →
16Projected 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 →
7.3–2595% 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 →
±36.3%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, Brewer's Sparrow in Great Basin is projected to stay roughly flat through 2029, near 16 (95% range 7.3–25). A 5-year backtest shows a typical error of ±36.3%, with 100% 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 →
2025167.525
2026167.425
2027167.425
2028167.325
2029167.325

Routes In Great Basin

Routes recording Brewer's Sparrow in Great Basin.
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 →
PrincetonOREGON1441985
Charleston ReservoirNEVADA1382024
WagontireOREGON1322024
HawthorneNEVADA1062001
Dinner StaNEVADA991993
Bald Mtn.NEVADA862024
BlitzenOREGON861993
DuboisIDAHO792024
MizpahNEVADA752024
Fandango CanOREGON742024
Blitzen 2OREGON722024
Willow SpgOREGON711971
BodieCALIFORNIA702024
Lost RiverIDAHO692024
RanchograndeNEVADA672024
Lookout LakeOREGON671994
Crowley LakeCALIFORNIA662024
Walker CanNEVADA602024
Sheldon NwrNEVADA602019
Blizzard GapOREGON602024
Ruby ValleyNEVADA592001
MidasNEVADA562024
RavendaleCALIFORNIA522024
BuchananOREGON512024
HenryIDAHO501983

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