BirdAnalyst
Species · Utah · BBS 2026 Release · 1966–2025

Western Tanager Population Trend in Utah

All statesForest birds

Western Tanager in Utah has surged: up 147% on the route-weighted index since 1970.

+147%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 →
84Routes 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 Western Tanager 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 →

Western Tanager has surged in Utah: up 147% on the route-weighted index since 1970.

Western Tanager Population Forecast in Utah

If the recent trend holds, Western Tanager in Utah is projected to stay roughly flat through 2030, near 4.7 (95% range 3.4–6.0). A 5-year backtest shows a typical error of ±20.9%, with 100% of held-out values landing inside the 95% band.

-2%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 →
4.7Projected 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 →
3.4–6.095% 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 →
±20.9%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, Western Tanager in Utah is projected to stay roughly flat through 2030, near 4.7 (95% range 3.4–6.0). A 5-year backtest shows a typical error of ±20.9%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20264.43.15.8
20274.53.25.8
20284.63.25.9
20294.63.35.9
20304.73.46.0

Western Tanager Survey Routes in Utah

Routes recording Western Tanager 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 →
Woodruff2920252002
Ferron2720252000
Red Spur Mtn.2620231997
Dixie Nf2420251993
Gooseberry2020251994
Bryce Canyon2020251990
Grizzly Rdge1920251986
Skyline Driv1920251986
Soapstone1820251992
Beck 21820251990
Uintah Nf1719941987
Beaver1620251968
Beck1519871976
Fayette1520251992
Heber Mtn.1520251996
Richfield1420191994
La Sal 31420252007
Fish Lake Nf1220251992
Main Canyon1220251987
Lost Cr. Res1220181995
Alton 21220252021
Navajo Lake1020251968
La Sal1020001994
Newcastle820251997
Logan Canyon820191997

Western Tanager Population Trend in Other States

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