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

Bell's Vireo In Badlands and Prairies

All regionsBadlands and PrairiesForest birds

Bell's Vireo in Badlands and Prairies has fallen sharply: down 50% on the route-weighted index since 1969.

-50%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 →
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 →
46YearsYears 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 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 →

Bell's Vireo has fallen sharply in Badlands and Prairies: down 50% on the route-weighted index since 1969.

Bell's Vireo In Badlands and Prairies Population Forecast

If the recent trend holds, Bell's Vireo in Badlands and Prairies is projected to stay roughly flat through 2029, near 0.06 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±53.3%, 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 →
0.06Projected 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 →
0.00–0.1795% 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 →
±53.3%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, Bell's Vireo in Badlands and Prairies is projected to stay roughly flat through 2029, near 0.06 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±53.3%, 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 →
20250.070.000.17
20260.070.000.17
20270.060.000.17
20280.060.000.17
20290.060.000.17

Routes In Badlands and Prairies

Routes recording Bell's Vireo 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 →
RosebudSOUTH-DAKOTA72010
ChamberlainSOUTH-DAKOTA42011
Oglala Nat. Grass.NEBRASKA32002
CrookstonNEBRASKA22024
SolenNORTH-DAKOTA22017
WinnerSOUTH-DAKOTA22022
RockyfordSOUTH-DAKOTA22023
LaplantSOUTH-DAKOTA21971
PromiseSOUTH-DAKOTA22015
LacreekSOUTH-DAKOTA22023
Ft ThompsonSOUTH-DAKOTA12011
OwankaSOUTH-DAKOTA11985
OttumwaSOUTH-DAKOTA11973
Cedar PassSOUTH-DAKOTA11975
Fort PierreSOUTH-DAKOTA12021
MaurineSOUTH-DAKOTA12023
BadlandsSOUTH-DAKOTA12023
White RiverSOUTH-DAKOTA12013

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