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

Chestnut-collared Longspur In Badlands and Prairies

All regionsBadlands and PrairiesGrassland birds

Chestnut-collared Longspur in Badlands and Prairies has collapsed: down 76% on the route-weighted index since 1969.

-76%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 →
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 →
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 →

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 →

Chestnut-collared Longspur has collapsed in Badlands and Prairies: down 76% on the route-weighted index since 1969.

Chestnut-collared Longspur In Badlands and Prairies Population Forecast

If the recent trend holds, Chestnut-collared Longspur in Badlands and Prairies is projected to fall about 100% by 2030 — from 5.7 in 2025 to a central estimate of 0.00 (95% range 0.00–17). A 5-year backtest shows a typical error of ±184.8%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1795% 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 →
±184.8%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, Chestnut-collared Longspur in Badlands and Prairies is projected to fall about 100% by 2030 — from 5.7 in 2025 to a central estimate of 0.00 (95% range 0.00–17). A 5-year backtest shows a typical error of ±184.8%, 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 →
20260.000.0017
20270.000.0017
20280.000.0017
20290.000.0017
20300.000.0017

Routes In Badlands and Prairies

Routes recording Chestnut-collared Longspur 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 →
Coleman CouleeMONTANA952024
RoundupMONTANA772025
Dinosaurs H.M.MONTANA742025
Cedar CreekNORTH-DAKOTA692022
LodgepoleSOUTH-DAKOTA512025
AlbionMONTANA372025
WebsterMONTANA312025
Dunn CenterNORTH-DAKOTA262025
ZapNORTH-DAKOTA242024
CarsonNORTH-DAKOTA202025
GorhamNORTH-DAKOTA192025
CircleMONTANA162023
Ft YatesNORTH-DAKOTA162004
RevaSOUTH-DAKOTA142025
Jordan SouthMONTANA132025
DickinsonNORTH-DAKOTA132025
LarkNORTH-DAKOTA121982
BowmanNORTH-DAKOTA122025
Wheat BasinMONTANA92025
Glen UllinNORTH-DAKOTA92025
FlatwillowMONTANA82006
Pine TreeWYOMING81995
LuskWYOMING82025
BentleyNORTH-DAKOTA72024
SolenNORTH-DAKOTA72025

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