BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Western Tanager In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauGeneralists

Western Tanager in Southern Rockies / Colorado Plateau has surged: up 197% on the route-weighted index since 1970.

+197%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 →
186Routes In RegionSurvey 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 SignalsNotable 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 Southern Rockies / Colorado Plateau: up 197% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Western Tanager in Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2029, near 6.7 (95% range 5.0–8.4). A 5-year backtest shows a typical error of ±7.1%, with 100% of held-out values landing inside the 95% band.

-3%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 →
6.7Projected 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 →
5.0–8.495% 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 →
±7.1%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 Southern Rockies / Colorado Plateau is projected to stay roughly flat through 2029, near 6.7 (95% range 5.0–8.4). A 5-year backtest shows a typical error of ±7.1%, 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 →
20256.44.78.1
20266.54.88.1
20276.64.98.2
20286.65.08.3
20296.75.08.4

Routes In Southern Rockies / Colorado Plateau

Routes recording Western Tanager in Southern Rockies / Colorado Plateau.
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 →
Buffalo ParkCOLORADO512023
Dolores RivCOLORADO402024
Angel Fire 2NEW-MEXICO382024
Mcphee Res.COLORADO362024
TsaileARIZONA322023
VallecitosNEW-MEXICO322024
Dixie NfUTAH292024
Dry ParkARIZONA282024
South ForkCOLORADO272024
Angel FireNEW-MEXICO272002
FerronUTAH262022
Red Spur Mtn.UTAH262023
Dunckley PasCOLORADO242024
Baxter PassCOLORADO232024
HeeneyCOLORADO222019
Mt. TaylorNEW-MEXICO222012
Douglas PassCOLORADO212024
Cheesman LkCOLORADO212024
Ojo SarcoNEW-MEXICO212024
Grizzly RdgeUTAH202024
Fox CreekCOLORADO192024
Comanche PkCOLORADO192024
Moon PassCOLORADO192024
Bluewater LakeNEW-MEXICO192021
GooseberryUTAH192024

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