BirdAnalyst
Species · BCR 17 · BBS 2025 Release · 1966–2024

Brown-headed Cowbird In Badlands and Prairies

All regionsBadlands and PrairiesGeneralists

Brown-headed Cowbird in Badlands and Prairies has surged: up 82% on the route-weighted index since 1969.

+82%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 →
138Routes 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 →
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 SignalsNotable 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 increasecomputed 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 →

Brown-headed Cowbird has surged in Badlands and Prairies: up 82% on the route-weighted index since 1969.

Brown-headed Cowbird In Badlands and Prairies Population Forecast

If the recent trend holds, Brown-headed Cowbird in Badlands and Prairies is projected to rise about 31% by 2029 — from 30 in 2024 to a central estimate of 39 (95% range 28–51). A 5-year backtest shows a typical error of ±32.3%, with 60% of held-out values landing inside the 95% band.

+31%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 →
39Projected 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 →
28–5195% 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 →
±32.3%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-headed Cowbird in Badlands and Prairies is projected to rise about 31% by 2029 — from 30 in 2024 to a central estimate of 39 (95% range 28–51). A 5-year backtest shows a typical error of ±32.3%, with 60% 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 →
2025382650
2026382750
2027392751
2028392751
2029392851

Routes In Badlands and Prairies

Routes recording Brown-headed Cowbird in Badlands and Prairies.
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 →
Ft ThompsonSOUTH-DAKOTA1942011
BentleyNORTH-DAKOTA1672024
Ft YatesNORTH-DAKOTA1622004
MaurineSOUTH-DAKOTA1602024
PromiseSOUTH-DAKOTA1542015
RosebudSOUTH-DAKOTA1182011
CarsonNORTH-DAKOTA1152024
GorhamNORTH-DAKOTA1112018
Cedar CreekNORTH-DAKOTA902022
DickinsonNORTH-DAKOTA872024
SolenNORTH-DAKOTA832024
IsabelSOUTH-DAKOTA832015
ZapNORTH-DAKOTA772024
OwankaSOUTH-DAKOTA752022
Glen UllinNORTH-DAKOTA712022
OttumwaSOUTH-DAKOTA682022
Eagle ButteSOUTH-DAKOTA672015
PowdervilleMONTANA662024
AlbionMONTANA652024
CrookstonNEBRASKA642024
MarcusSOUTH-DAKOTA622015
Fort PierreSOUTH-DAKOTA612024
ChamberlainSOUTH-DAKOTA592011
VolunteerSOUTH-DAKOTA592019
Railroad ButteSOUTH-DAKOTA592022

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