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Species · Wyoming · BBS 2025 Release · 1966–2024

Chestnut-collared Longspur Population Trend in Wyoming

All statesGeneralists

Chestnut-collared Longspur in Wyoming has collapsed: down 80% on the route-weighted index since 1981.

-80%Since 1981TrendPercent 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 →
16Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
43YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Chestnut-collared Longspur Trends in WyomingNotable 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 Wyoming: down 80% on the route-weighted index since 1981.

Chestnut-collared Longspur Population Forecast in Wyoming

If the recent trend holds, Chestnut-collared Longspur in Wyoming is projected to fall about 100% by 2029 — from 0.33 in 2024 to a central estimate of 0.00 (95% range 0.00–0.83). A 5-year backtest shows a typical error of ±76.3%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.8395% 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 →
±76.3%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 →
19782029
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 →
20250.050.000.89
20260.030.000.86
20270.010.000.84
20280.000.000.83
20290.000.000.83

Chestnut-collared Longspur Survey Routes in Wyoming

Routes recording Chestnut-collared Longspur in Wyoming.
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 →
Cheyenne2120241980
Pine Tree819951980
Caballa Crk520211996
Lusk520241989
Clarkelen319781978
Rawlins320051993
Mayoworth320242024
Raven219951995
Rock River220221993
Piney219871980
Clark120111990
Harland Flat120171990
Highlight120071980
Baggs119951995
Rozet120231991
Ethete119921992

Chestnut-collared Longspur Population Trend in Other States

coloradominnesotamontananebraskanorth-dakotasouth-dakota

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