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

Western Tanager Population Trend in Utah

All statesGeneralists

Western Tanager in Utah has surged: up 135% on the route-weighted index since 1970.

+135%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 →
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 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 134% 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 rise about 28% by 2029 — from 3.6 in 2024 to a central estimate of 4.6 (95% range 3.3–5.9). A 5-year backtest shows a typical error of ±30%, with 100% of held-out values landing inside the 95% band.

+28%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 →
4.6Projected 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 →
3.3–5.995% 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 →
±30%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 rise about 28% by 2029 — from 3.6 in 2024 to a central estimate of 4.6 (95% range 3.3–5.9). A 5-year backtest shows a typical error of ±30%, 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 →
20254.33.05.7
20264.43.15.7
20274.53.15.8
20284.53.25.8
20294.63.35.9

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 →
Dixie Nf2920241993
Ferron2620222000
Red Spur Mtn.2620231997
Grizzly Rdge2020241986
Gooseberry1920241994
Uintah Nf1719941987
Fish Lake Nf1720241992
Heber Mtn.1620241996
Beck1519871976
Woodruff1520242002
Navajo Lake1420241968
Richfield1420191994
Beck 21420181990
La Sal 31320242007
Fayette1220211992
Lost Cr. Res1220181995
Bryce Canyon1120241990
La Sal1020001994
Beaver920241968
Alton 2920242021
Logan Canyon820191997
Soapstone720241992
Main Canyon620241987
La Sal 2620062003
Wasatch Nf520241988

Western Tanager Population Trend in Other States

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