Species · Colorado · BBS 2025 Release · 1966–2024
California Gull Population Trend in Colorado
California Gull in Colorado has surged: up 148× on the route-weighted index since 1986.
148×Since 1986
15Routes In State
40Years
Notable California Gull Trends in Colorado
long arc increasecomputed index
California Gull has surged in Colorado: up 148× on the route-weighted index since 1986.
California Gull Population Forecast in Colorado
If the recent trend holds, California Gull in Colorado is projected to stay roughly flat through 2029, near 9.9 (95% range 3.4–16). A 5-year backtest shows a typical error of ±41.3%, with 60% of held-out values landing inside the 95% band.
-4%Change by 2029
9.9Projected 2029 index
3.4–1695% range
±41.3%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 8.8 | 2.4 | 15 |
| 2026 | 9.1 | 2.6 | 16 |
| 2027 | 9.4 | 2.9 | 16 |
| 2028 | 9.6 | 3.1 | 16 |
| 2029 | 9.9 | 3.4 | 16 |
California Gull Survey Routes in Colorado
| Guffey | 982 | 2024 | 1992 |
| Briggsdale | 95 | 2023 | 1981 |
| Tincup | 22 | 2011 | 1994 |
| Walden | 9 | 2024 | 1991 |
| Hudson | 9 | 2024 | 1988 |
| Lost Lake | 4 | 2010 | 2001 |
| Fort Morgan | 4 | 2000 | 2000 |
| Harmony | 3 | 2018 | 1992 |
| Julesburg | 3 | 2002 | 2002 |
| Tarryall | 2 | 2023 | 1990 |
| Yampa | 1 | 2010 | 2010 |
| Stillwater Pass | 1 | 2006 | 1999 |
| Weston Pass | 1 | 2000 | 1995 |
| Como | 1 | 1998 | 1998 |
| Doyle Bridge | 1 | 1994 | 1992 |
California Gull Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.