BirdAnalyst
Species · BCR 17 · BBS 2026 Release · 1966–2025

Brewer's Sparrow In Badlands and Prairies

All regionsBadlands and PrairiesArid-land birds

Brewer's Sparrow in Badlands and Prairies has held roughly steady: down 2% on the route-weighted index since 1970.

-2%Since 1970TrendPercent 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 →
76Routes 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 →

No notable trend signals for Brewer's Sparrow in Badlands and Prairies. See the full index history below.

Brewer's Sparrow In Badlands and Prairies Population Forecast

If the recent trend holds, Brewer's Sparrow in Badlands and Prairies is projected to fall about 48% by 2030 — from 4.5 in 2025 to a central estimate of 2.3 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±37.2%, with 100% of held-out values landing inside the 95% band.

-48%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 →
2.3Projected 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 →
0.00–5.195% 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 →
±37.2%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, Brewer's Sparrow in Badlands and Prairies is projected to fall about 48% by 2030 — from 4.5 in 2025 to a central estimate of 2.3 (95% range 0.00–5.1). A 5-year backtest shows a typical error of ±37.2%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20262.50.005.2
20272.40.005.2
20282.40.005.2
20292.40.005.1
20302.30.005.1

Routes In Badlands and Prairies

Routes recording Brewer's Sparrow 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 →
BucknumWYOMING772024
Custer 2MONTANA562025
SavagetonWYOMING442025
CusterMONTANA372022
Harland FlatWYOMING292025
ClarkelenWYOMING281978
Thunder BasinWYOMING232025
HighlightWYOMING212007
RozetWYOMING212025
RoundupMONTANA202025
PowdervilleMONTANA192025
Caballa CrkWYOMING192021
PineyWYOMING181990
RavenWYOMING182025
LeroyMONTANA172025
ShawneeWYOMING172025
Teapot DomeWYOMING161989
SchoonoverWYOMING152025
WinnettMONTANA142025
Flatwillow 2MONTANA132023
GlenrockWYOMING131977
UptonWYOMING132025
Two DotMONTANA102009
IngomarMONTANA102023
WyarnoWYOMING102025

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