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

Curve-billed Thrasher In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauArid-land birds

Curve-billed Thrasher in Southern Rockies / Colorado Plateau has edged up: up 11% on the route-weighted index since 1971.

+11%Since 1971TrendPercent 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 →
19Routes 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 →
47YearsYears 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 →

No notable trend signals for Curve-billed Thrasher in Southern Rockies / Colorado Plateau. See the full index history below.

Curve-billed Thrasher In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Curve-billed Thrasher in Southern Rockies / Colorado Plateau is projected to fall about 14% by 2029 — from 0.09 in 2024 to a central estimate of 0.08 (95% range 0.00–0.22). A 5-year backtest shows a typical error of ±137.2%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.08Projected 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 →
0.00–0.2295% 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 →
±137.2%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 Southern Rockies / Colorado Plateau is projected to fall about 14% by 2029 — from 0.09 in 2024 to a central estimate of 0.08 (95% range 0.00–0.22). A 5-year backtest shows a typical error of ±137.2%, 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 →
20250.080.000.22
20260.080.000.22
20270.080.000.22
20280.080.000.22
20290.080.000.22

Routes In Southern Rockies / Colorado Plateau

Routes recording Curve-billed Thrasher 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 →
MountainairNEW-MEXICO62024
PasturaNEW-MEXICO32024
Rose WellsARIZONA21973
TorreonNEW-MEXICO22012
La CienegaNEW-MEXICO22022
ClaunchNEW-MEXICO21998
QuemadoNEW-MEXICO21997
Gallo ArroyoNEW-MEXICO22018
Mt TrumbullARIZONA11980
House RockARIZONA12007
The GapARIZONA11968
YampaiARIZONA11976
Peach SpringARIZONA12023
ParlinCOLORADO12002
Gribbles PrkCOLORADO12024
CebollaNEW-MEXICO12010
Horse MtnNEW-MEXICO12024
Cerro VerdeNEW-MEXICO12019
Claunch 2NEW-MEXICO12024

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