BirdAnalyst
Species · BCR 34 · BBS 2025 Release · 1966–2024

Western Tanager In Sierra Madre Occidental

All regionsSierra Madre OccidentalGeneralists

Western Tanager in Sierra Madre Occidental has surged: up 674% on the route-weighted index since 1970.

+674%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 →
29Routes 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 →
54YearsYears 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 Sierra Madre Occidental: up 674% on the route-weighted index since 1970.

Forecast

If the recent trend holds, Western Tanager in Sierra Madre Occidental is projected to rise about 176% by 2029 — from 2.8 in 2024 to a central estimate of 7.8 (95% range 3.6–12). A 5-year backtest shows a typical error of ±52%, with 80% of held-out values landing inside the 95% band.

+176%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 →
7.8Projected 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 →
3.6–1295% 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 →
±52%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 Sierra Madre Occidental is projected to rise about 176% by 2029 — from 2.8 in 2024 to a central estimate of 7.8 (95% range 3.6–12). A 5-year backtest shows a typical error of ±52%, with 80% 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 →
20257.53.312
20267.63.412
20277.73.512
20287.83.512
20297.83.612

Routes In Sierra Madre Occidental

Routes recording Western Tanager in Sierra Madre Occidental.
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 →
Mt. GrahamARIZONA452023
ReserveNEW-MEXICO422023
FlagstaffARIZONA352022
Happy JackARIZONA332024
AlpineARIZONA212023
PrescottARIZONA172022
SprucedaleARIZONA172023
WilliamsARIZONA132019
RedingtonARIZONA122023
PinetopARIZONA102022
Aztec PeakARIZONA71978
BlueARIZONA71991
PortalARIZONA52024
Emory PassNEW-MEXICO52024
PomereneARIZONA42022
Forest LakesARIZONA32024
RuckerARIZONA32009
SunizonaARIZONA21986
Tonto Vill.ARIZONA22021
Carr MtnARIZONA22024
Mormon LakeARIZONA11975
Peña BlancaARIZONA12024
MaineARIZONA12022
Skull ValleyARIZONA12011
Clay SpringARIZONA12024

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