Species · Colorado · BBS 2025 Release · 1966–2024
Black-crowned Night Heron Population Trend in Colorado
Black-crowned Night Heron in Colorado has collapsed: down 94% on the route-weighted index since 1970.
-94%Since 1970
19Routes In State
46Years
Notable Black-crowned Night Heron Trends in Colorado
long arc declinecomputed index
Black-crowned Night Heron has collapsed in Colorado: down 94% on the route-weighted index since 1970.
Black-crowned Night Heron Population Forecast in Colorado
If the recent trend holds, Black-crowned Night Heron in Colorado is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.21). A 5-year backtest shows a typical error of ±133.5%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2029
0.00Projected 2029 index
0.00–0.2195% range
±133.5%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.00 | 0.00 | 0.21 |
| 2026 | 0.00 | 0.00 | 0.21 |
| 2027 | 0.00 | 0.00 | 0.21 |
| 2028 | 0.00 | 0.00 | 0.21 |
| 2029 | 0.00 | 0.00 | 0.21 |
Black-crowned Night Heron Survey Routes in Colorado
| Rio Grnds Rs | 12 | 1999 | 1993 |
| Buford | 3 | 1984 | 1984 |
| Neegrande | 3 | 2018 | 1998 |
| Last Chance | 2 | 2004 | 1988 |
| Powderhorn | 2 | 1999 | 1999 |
| Mosca | 2 | 2008 | 1999 |
| San Luis | 2 | 2009 | 1997 |
| Harmony | 1 | 1995 | 1979 |
| Arsenal | 1 | 2009 | 1993 |
| Moffat | 1 | 1979 | 1970 |
| Dolores | 1 | 1985 | 1968 |
| Blanca | 1 | 1980 | 1980 |
| Walden | 1 | 2019 | 2019 |
| Hudson | 1 | 2013 | 1988 |
| Pinos Creek | 1 | 1988 | 1988 |
| Alamosa | 1 | 2024 | 1991 |
| Groundhog Rs | 1 | 1994 | 1994 |
| Moon Pass | 1 | 2003 | 1998 |
| Lake City 2 | 1 | 2018 | 2018 |
Black-crowned Night Heron Population Trend in Other States
alabamaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.