Species · Colorado · BBS 2025 Release · 1966–2024
Chestnut-collared Longspur Population Trend in Colorado
Chestnut-collared Longspur in Colorado has collapsed: down 95% on the route-weighted index since 1977.
-95%Since 1977
12Routes In State
39Years
Notable Chestnut-collared Longspur Trends in Colorado
long arc declinecomputed index
Chestnut-collared Longspur has collapsed in Colorado: down 95% on the route-weighted index since 1977.
Chestnut-collared Longspur Population Forecast in Colorado
If the recent trend holds, Chestnut-collared Longspur in Colorado is projected to fall about 100% by 2029 — from 0.07 in 2024 to a central estimate of 0.00 (95% range 0.00–0.49). A 5-year backtest shows a typical error of ±486%, with 100% of held-out values landing inside the 95% band.
-100%Change by 2029
0.00Projected 2029 index
0.00–0.4995% range
±486%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.49 |
| 2026 | 0.00 | 0.00 | 0.49 |
| 2027 | 0.00 | 0.00 | 0.49 |
| 2028 | 0.00 | 0.00 | 0.49 |
| 2029 | 0.00 | 0.00 | 0.49 |
Chestnut-collared Longspur Survey Routes in Colorado
Chestnut-collared Longspur Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.