BirdAnalyst
Species · BCR 35 · BBS 2025 Release · 1966–2024

Western Tanager In Chihuahuan Desert

All regionsChihuahuan DesertGeneralists

Western Tanager in Chihuahuan Desert has surged: up 15× on the route-weighted index since 1977.

15×Since 1977TrendPercent 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 →
12Routes 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 →
45YearsYears 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 Chihuahuan Desert: up 15× on the route-weighted index since 1977.

Forecast

If the recent trend holds, Western Tanager in Chihuahuan Desert is projected to fall about 16% by 2029 — from 2.4 in 2024 to a central estimate of 2.0 (95% range 1.2–2.8). A 5-year backtest shows a typical error of ±22.5%, with 80% of held-out values landing inside the 95% band.

-16%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 →
2.0Projected 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 →
1.2–2.895% 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 →
±22.5%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 Chihuahuan Desert is projected to fall about 16% by 2029 — from 2.4 in 2024 to a central estimate of 2.0 (95% range 1.2–2.8). A 5-year backtest shows a typical error of ±22.5%, with 80% of held-out values landing inside the 95% band.19742029
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 →
20251.91.12.7
20261.91.12.7
20271.91.12.7
20282.01.12.8
20292.01.22.8

Routes In Chihuahuan Desert

Routes recording Western Tanager in Chihuahuan Desert.
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 →
CloudcroftNEW-MEXICO622024
PinonNEW-MEXICO52024
Salt FlatTEXAS32013
RodeoNEW-MEXICO21974
CarrizozoNEW-MEXICO12024
RoswellNEW-MEXICO11974
Capitan Mtn.NEW-MEXICO12011
QueenNEW-MEXICO12021
AltudaTEXAS11980
Bear MtnTEXAS12024
ToyahvaleTEXAS12017
MarfaTEXAS12019

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