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Species · Utah · BBS 2026 Release · 1966–2025

Brewer's Sparrow Population Trend in Utah

All statesArid-land birds

Brewer's Sparrow in Utah has risen sharply: up 66% on the route-weighted index since 1971.

+66%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 →
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 UtahNotable 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 risen sharply in Utah: up 66% on the route-weighted index since 1971.

Brewer's Sparrow Population Forecast in Utah

If the recent trend holds, Brewer's Sparrow in Utah is projected to rise about 11% by 2030 — from 10 in 2025 to a central estimate of 12 (95% range 3.3–20). A 5-year backtest shows a typical error of ±71.7%, with 100% of held-out values landing inside the 95% band.

+11%Change by 2030TrendPercent 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 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
3.3–2095% 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 →
±71.7%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 Utah is projected to rise about 11% by 2030 — from 10 in 2025 to a central estimate of 12 (95% range 3.3–20). A 5-year backtest shows a typical error of ±71.7%, with 100% of held-out values landing inside the 95% band.19692030
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 →
2026113.120
2027123.220
2028123.220
2029123.220
2030123.320

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
Beck 26820251990
Altonah5620251969
M Warner Res5320251994
Crawford Mts5120232004
Iron Springs5020191985
Fish Lake Nf4520251992
Beck4019871969
Gold Hill3820251987
Monticello3620251998
Vernon3520251992
Grantsville3520252001
Vernal3520182003
Wendover3420111986
Lost Cr. Res3420181995
E. Bear Lake3320251995
Grouse Creek3220101982
Ant Flat-Ogden Can3120251994
Moon Lake 22720232004
Uintah Nf2519941987
Fayette2420251992
Skyline Driv2220251986
Fish Springs1820251988
Heber Mtn.1620251996

Brewer's Sparrow Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.