BirdAnalyst
Species · Colorado · BBS 2025 Release · 1966–2024

Curve-billed Thrasher Population Trend in Colorado

All statesArid-land birds

Curve-billed Thrasher in Colorado has increased: up 46% on the route-weighted index since 1981.

+46%Since 1981
14Routes In State
34Years

Notable Curve-billed Thrasher Trends in Colorado

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

Curve-billed Thrasher Population Forecast in Colorado

If the recent trend holds, Curve-billed Thrasher in Colorado is projected to fall about 44% by 2029 — from 0.08 in 2024 to a central estimate of 0.05 (95% range 0.01–0.09). A 5-year backtest shows a typical error of ±49.8%, with 80% of held-out values landing inside the 95% band.

-44%Change by 2029
0.05Projected 2029 index
0.01–0.0995% range
±49.8%Backtest error
19732029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.040.000.09
20260.040.000.09
20270.050.000.09
20280.050.010.09
20290.050.010.09

Curve-billed Thrasher Survey Routes in Colorado

Routes recording Curve-billed Thrasher in Colorado.
Villegreen320241989
Crowley220241990
Gribbles Prk120242024
Sheridan Lak120062006
Ninaview120152006
Campo120181998
Doyle Bridge 2120182018
Timpas120192004
Parlin120022002
Mica Butte119811973
Gilpin120241993
Neegrande120122002
Cone Mtn120241989
Ellicott120192006

Curve-billed Thrasher Population Trend in Other States

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