BirdAnalyst
Species · Nevada · BBS 2025 Release · 1966–2024

Brewer's Sparrow Population Trend in Nevada

All statesGeneralists

Brewer's Sparrow in Nevada has surged: up 88% on the route-weighted index since 1970.

+88%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 →
50Routes In StateSurvey 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 Brewer's Sparrow Trends in NevadaNotable 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 →

Brewer's Sparrow has surged in Nevada: up 88% on the route-weighted index since 1970.

Brewer's Sparrow Population Forecast in Nevada

If the recent trend holds, Brewer's Sparrow in Nevada is projected to rise about 18% by 2029 — from 24 in 2024 to a central estimate of 29 (95% range 0.00–64). A 5-year backtest shows a typical error of ±58.7%, with 100% of held-out values landing inside the 95% band.

+18%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 →
29Projected 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 →
0.00–6495% 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 →
±58.7%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, Brewer's Sparrow in Nevada is projected to rise about 18% by 2029 — from 24 in 2024 to a central estimate of 29 (95% range 0.00–64). A 5-year backtest shows a typical error of ±58.7%, 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 →
2025290.0064
2026290.0064
2027290.0064
2028290.0064
2029290.0064

Brewer's Sparrow Survey Routes in Nevada

Routes recording Brewer's Sparrow in 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 →
Charleston Reservoir13820242024
Hawthorne10620011997
Dinner Sta9919931968
Bald Mtn.8620241992
Mizpah7520241988
Ranchogrande6720241988
Walker Can6020241969
Sheldon Nwr6020191992
Ruby Valley5920011997
Midas5620241974
Chimney Res.4420242005
Dobbin Creek4120181968
Jarbidge3820151997
Austin3820182008
Toiyabe Nf3220241987
Humboldt Nf 23120242021
Sutcliffe3019711968
Fish Creek2820211997
Eureka2720241968
Hiko2420231971
Humboldt Nf1920191993
Darroughs Hot Spgs1620242002
Big Smokey V1519881988
Willis1320241988
Carson River1320052001

Brewer's Sparrow Population Trend in Other States

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