BirdAnalyst
Species · BCR 19 · BBS 2025 Release · 1966–2024

Curve-billed Thrasher In Central Mixed Grass Prairie

All regionsCentral Mixed Grass PrairieArid-land birds

Curve-billed Thrasher in Central Mixed Grass Prairie has increased: up 40% on the route-weighted index since 1975.

+40%Since 1975TrendPercent 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 →
18Routes 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 →
48YearsYears 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 Central Mixed Grass Prairie. See the full index history below.

Forecast

If the recent trend holds, Curve-billed Thrasher in Central Mixed Grass Prairie is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±156.1%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00–0.2695% 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 →
±156.1%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, Curve-billed Thrasher in Central Mixed Grass Prairie is projected to stay roughly flat through 2029, near 0.08 (95% range 0.00–0.26). A 5-year backtest shows a typical error of ±156.1%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.080.000.27
20260.080.000.26
20270.080.000.26
20280.080.000.26
20290.080.000.26

Routes In Central Mixed Grass Prairie

Routes recording Curve-billed Thrasher in Central Mixed Grass Prairie.
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 →
WeinertTEXAS81994
SilverTEXAS32019
St JohnKANSAS22010
MertzonTEXAS22019
ChildressTEXAS22016
HackberryTEXAS21980
RotanTEXAS22021
GirardTEXAS22023
MisslerKANSAS11981
Pear ValleyTEXAS12024
GraybackTEXAS12022
ClarendonTEXAS12019
EldoradoTEXAS11975
HaskellTEXAS12024
HawleyTEXAS12007
WilliamsTEXAS12021
LakeviewTEXAS12004
Shields 2TEXAS12023

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