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

Western Tanager Population Trend in Arizona

All statesForest birds

Western Tanager in Arizona has surged: up 17× on the route-weighted index since 1970.

17×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 →
38Routes 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 →
57YearsYears 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 ArizonaNotable 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 Arizona: up 17× on the route-weighted index since 1970.

Western Tanager Population Forecast in Arizona

If the recent trend holds, Western Tanager in Arizona is projected to fall about 16% by 2030 — from 5.5 in 2025 to a central estimate of 4.7 (95% range 2.0–7.3). A 5-year backtest shows a typical error of ±32.5%, with 100% of held-out values landing inside the 95% band.

-16%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 →
2.0–7.395% 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 →
±32.5%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 Arizona is projected to fall about 16% by 2030 — from 5.5 in 2025 to a central estimate of 4.7 (95% range 2.0–7.3). A 5-year backtest shows a typical error of ±32.5%, 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 →
20264.51.87.1
20274.51.87.2
20284.61.97.2
20294.61.97.3
20304.72.07.3

Western Tanager Survey Routes in Arizona

Routes recording Western Tanager in Arizona.
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 →
Dry Park3920251992
Williams3420251993
Tsaile3220231993
Mt. Graham2820251995
Happy Jack2720251977
Flagstaff2020251988
Sprucedale1920251992
Tonto Vill.1720251992
Alpine1720251993
Sawmill1020141988
Pinetop1020221993
Portal720251975
Prescott720251974
Aztec Peak719781974
Blue719911974
Redington520252022
Pomerene420221971
Rucker320091995
Wikieup320121992
Skull Valley 2320252025
House Rock220221971
Round Rock219761970
Sunizona219861970
Maine220251992
Forest Lakes220251992

Western Tanager Population Trend in Other States

alaskacaliforniacoloradoidahomontananebraskanevadanew-mexicooregonsouth-dakotatexasutahwashingtonwyoming

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