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

Curve-billed Thrasher Population Trend in Texas

All statesArid-land birds

Curve-billed Thrasher in Texas has fallen sharply: down 73% on the route-weighted index since 1969.

-73%Since 1969TrendPercent 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 →
128Routes In StateSurvey 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 Curve-billed Thrasher Trends in TexasNotable 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 declinecomputed 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 fallen sharply in Texas: down 73% on the route-weighted index since 1969.

Curve-billed Thrasher Population Forecast in Texas

If the recent trend holds, Curve-billed Thrasher in Texas is projected to fall about 23% by 2029 — from 0.65 in 2024 to a central estimate of 0.50 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±18%, with 100% of held-out values landing inside the 95% band.

-23%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 →
0.50Projected 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 →
0.00–1.395% 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 →
±18%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 Texas is projected to fall about 23% by 2029 — from 0.65 in 2024 to a central estimate of 0.50 (95% range 0.00–1.3). A 5-year backtest shows a typical error of ±18%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.570.001.4
20260.560.001.4
20270.540.001.3
20280.520.001.3
20290.500.001.3

Curve-billed Thrasher Survey Routes in Texas

Routes recording Curve-billed Thrasher in Texas.
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 →
Millett1420121995
Millett 21320242015
Encinal1220101969
Pumpville1220242006
Cavasara Cr.1020231996
Guerra920181988
Agua Nueva820231969
George West820241967
Weinert819941987
Comstock820171973
Girvin820241979
Encinal 2720242011
Randado620241967
Cornudas620181968
Catarina 2620172011
Kermit619941994
Mentone620151999
Ft. Davis620232004
Pecos620172017
Rachal520231967
El Sauz520231993
San Pedro520172010
Zapata419871967
San Saba419941980
Rankin420241967

Curve-billed Thrasher Population Trend in Other States

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