BirdAnalyst
Species · BCR 34 · BBS 2026 Release · 1966–2025

Curve-billed Thrasher In Sierra Madre Occidental

All regionsSierra Madre OccidentalArid-land birds

Curve-billed Thrasher in Sierra Madre Occidental has surged: up 100% on the route-weighted index since 1970.

+100%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 →
22Routes 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 →
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 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 →

Curve-billed Thrasher has surged in Sierra Madre Occidental: up 100% on the route-weighted index since 1970.

Curve-billed Thrasher In Sierra Madre Occidental Population Forecast

If the recent trend holds, Curve-billed Thrasher in Sierra Madre Occidental is projected to rise about 43% by 2030 — from 1.9 in 2025 to a central estimate of 2.6 (95% range 1.4–3.9). A 5-year backtest shows a typical error of ±42.6%, with 80% of held-out values landing inside the 95% band.

+43%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 →
2.6Projected 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 →
1.4–3.995% 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 →
±42.6%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, Curve-billed Thrasher in Sierra Madre Occidental is projected to rise about 43% by 2030 — from 1.9 in 2025 to a central estimate of 2.6 (95% range 1.4–3.9). A 5-year backtest shows a typical error of ±42.6%, with 80% 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 →
20262.51.33.8
20272.61.43.8
20282.61.43.8
20292.61.43.8
20302.61.43.9

Routes In Sierra Madre Occidental

Routes recording Curve-billed Thrasher 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 →
Bartlett ResARIZONA172025
CutterARIZONA162014
SahuaritaARIZONA112025
SunizonaARIZONA91997
DragoonARIZONA62009
PatagoniaARIZONA52025
Aztec PeakARIZONA31978
AmadoARIZONA32025
Carr MtnARIZONA32025
PortalARIZONA32025
RedingtonARIZONA22025
PomereneARIZONA12025
San SimonARIZONA12024
Peña BlancaARIZONA12025
Mt. GrahamARIZONA12018
McnealARIZONA12025
Clay SpringARIZONA12025
Sunizona 2ARIZONA12025
RuckerARIZONA12007
Vicks PeakNEW-MEXICO12006
Emory PassNEW-MEXICO12025
MagdalenaNEW-MEXICO12021

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