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

Brewer's Sparrow Population Trend in Utah

All statesGeneralists

Brewer's Sparrow in Utah has increased: up 45% on the route-weighted index since 1971.

+45%Since 1971TrendPercent 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 →
108Routes 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 →
55YearsYears 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 UtahNotable 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 Utah. See the full index history below.

Brewer's Sparrow Population Forecast in Utah

If the recent trend holds, Brewer's Sparrow in Utah is projected to rise about 101% by 2029 — from 5.8 in 2024 to a central estimate of 12 (95% range 3.2–20). A 5-year backtest shows a typical error of ±73.3%, with 100% of held-out values landing inside the 95% band.

+101%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 →
12Projected 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 →
3.2–2095% 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 →
±73.3%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 Utah is projected to rise about 101% by 2029 — from 5.8 in 2024 to a central estimate of 12 (95% range 3.2–20). A 5-year backtest shows a typical error of ±73.3%, with 100% of held-out values landing inside the 95% band.19692029
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 →
2025123.120
2026123.120
2027123.120
2028123.220
2029123.220

Brewer's Sparrow Survey Routes in Utah

Routes recording Brewer's Sparrow in Utah.
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 →
Neponset Res10820181995
Saleratus Cr7220181995
M Warner Res5320241994
Crawford Mts5120232004
Iron Springs5020191985
Beck4019871969
Altonah4020151969
Vernal3520182003
Wendover3420111986
Lost Cr. Res3420181995
Fish Lake Nf3320241992
Grouse Creek3220101982
Blanding3120231987
Moon Lake 22720232004
Goose Creek Mtn.2720231997
Ant Flat-Ogden Can2620231994
Lynn2520231983
Uintah Nf2519941987
Grantsville2520242001
Randolph2120241992
Canyon Rims2020241998
Gold Hill1920241987
E. Bear Lake1820221995
Beck 21720181990
Snowville1720241999

Brewer's Sparrow Population Trend in Other States

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