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

Fox Sparrow Population Trend in Utah

All statesGeneralists

Fox Sparrow in Utah has fallen sharply: down 53% on the route-weighted index since 1979.

-53%Since 1979TrendPercent 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 →
21Routes 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 →
40YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Fox 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 declinecomputed 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 →

Fox Sparrow has fallen sharply in Utah: down 53% on the route-weighted index since 1979.

Fox Sparrow Population Forecast in Utah

If the recent trend holds, Fox Sparrow in Utah is projected to fall about 41% by 2029 — from 0.42 in 2024 to a central estimate of 0.25 (95% range 0.00–0.66). A 5-year backtest shows a typical error of ±60.3%, with 100% of held-out values landing inside the 95% band.

-41%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 →
0.25Projected 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 →
0.00–0.6695% 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 →
±60.3%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, Fox Sparrow in Utah is projected to fall about 41% by 2029 — from 0.42 in 2024 to a central estimate of 0.25 (95% range 0.00–0.66). A 5-year backtest shows a typical error of ±60.3%, with 100% of held-out values landing inside the 95% band.19752029
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 →
20250.260.000.67
20260.260.000.67
20270.260.000.66
20280.250.000.66
20290.250.000.66

Fox Sparrow Survey Routes in Utah

Routes recording Fox 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 →
Uintah Nf1319941990
Woodruff820242005
Lost Cr. Res720151995
Gooseberry720242013
Logan Canyon520192000
Soapstone420241992
Hardware Ranch420231994
Heber Mtn.320241996
Skyline Driv220061986
Moon Lake 2120232006
Hyrum119791975
Saleratus Cr120111997
Beaver119821979
Randolph120241997
Beck 2120061996
Hanna120231997
Ferron120212000
Ant Flat-Ogden Can120231995
Wasatch Nf120242001
Fish Lake Nf120242024
Main Canyon119931993

Fox Sparrow Population Trend in Other States

alaskacaliforniacoloradoidahomainemontananevadaoregonwashingtonwyoming

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