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

Abert's Towhee In Sierra Madre Occidental

All regionsSierra Madre OccidentalArid-land birds

Abert's Towhee in Sierra Madre Occidental has surged: up 75% on the route-weighted index since 1973.

+75%Since 1973TrendPercent 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 →
11Routes 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 →
46YearsYears 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 →

Abert's Towhee has surged in Sierra Madre Occidental: up 75% on the route-weighted index since 1973.

Abert's Towhee In Sierra Madre Occidental Population Forecast

If the recent trend holds, Abert's Towhee in Sierra Madre Occidental is projected to fall about 48% by 2029 — from 1.2 in 2024 to a central estimate of 0.64 (95% range 0.09–1.2). A 5-year backtest shows a typical error of ±35.1%, with 60% of held-out values landing inside the 95% band.

-48%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 →
0.64Projected 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 →
0.09–1.295% 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 →
±35.1%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, Abert's Towhee in Sierra Madre Occidental is projected to fall about 48% by 2029 — from 1.2 in 2024 to a central estimate of 0.64 (95% range 0.09–1.2). A 5-year backtest shows a typical error of ±35.1%, with 60% of held-out values landing inside the 95% band.19692029
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 →
20250.620.071.2
20260.630.071.2
20270.630.081.2
20280.630.081.2
20290.640.091.2

Routes In Sierra Madre Occidental

Routes recording Abert's Towhee 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 →
PomereneARIZONA92024
RedingtonARIZONA82023
Bartlett ResARIZONA72024
SunizonaARIZONA31997
Carr MtnARIZONA32024
Peña BlancaARIZONA22022
PatagoniaARIZONA22024
CutterARIZONA22014
San SimonARIZONA12019
AmadoARIZONA12017
SahuaritaARIZONA12024

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