BirdAnalyst
Species · BCR 18 · BBS 2026 Release · 1966–2025

Brown Thrasher In Shortgrass Prairie

All regionsShortgrass PrairieForest birds

Brown Thrasher in Shortgrass Prairie has declined: down 41% on the route-weighted index since 1969.

-41%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 →
71Routes 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 →
58YearsYears 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 Brown Thrasher in Shortgrass Prairie. See the full index history below.

Brown Thrasher In Shortgrass Prairie Population Forecast

If the recent trend holds, Brown Thrasher in Shortgrass Prairie is projected to stay roughly flat through 2030, near 0.52 (95% range 0.17–0.86). A 5-year backtest shows a typical error of ±33.7%, with 100% of held-out values landing inside the 95% band.

-3%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 →
0.52Projected 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 →
0.17–0.8695% 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 →
±33.7%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, Brown Thrasher in Shortgrass Prairie is projected to stay roughly flat through 2030, near 0.52 (95% range 0.17–0.86). A 5-year backtest shows a typical error of ±33.7%, with 100% of held-out values landing inside the 95% band.19672030
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 →
20260.500.160.85
20270.510.160.85
20280.510.160.86
20290.510.170.86
20300.520.170.86

Routes In Shortgrass Prairie

Routes recording Brown Thrasher in Shortgrass 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 →
PaxtonNEBRASKA122016
DaltonNEBRASKA92025
Hay SpringsNEBRASKA62025
JulesburgCOLORADO52021
TimpasCOLORADO52010
BrownsonNEBRASKA52021
Wildhorse LCOLORADO42025
KirkCOLORADO42023
RuletonKANSAS42022
KimballNEBRASKA42025
CrawfordNEBRASKA42019
FlemingCOLORADO32025
Last ChanceCOLORADO31999
BoyeroCOLORADO32016
Two ButtesCOLORADO32025
Prospect ValCOLORADO32000
BurlingtonCOLORADO32024
Murray LakeNEBRASKA32025
HardestyOKLAHOMA32004
GroverCOLORADO22024
Doyle BridgeCOLORADO21995
NeegrandeCOLORADO22024
Fort MorganCOLORADO22025
Sheridan LakCOLORADO22016
RockportCOLORADO22024

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