Species · South Dakota · BBS 2025 Release · 1966–2024
Black-crowned Night Heron Population Trend in South Dakota
Black-crowned Night Heron in South Dakota has collapsed: down 87% on the route-weighted index since 1969.
-87%Since 1969
20Routes In State
56Years
Notable Black-crowned Night Heron Trends in South Dakota
long arc declinecomputed index
Black-crowned Night Heron has collapsed in South Dakota: down 87% on the route-weighted index since 1969.
Black-crowned Night Heron Population Forecast in South Dakota
If the recent trend holds, Black-crowned Night Heron in South Dakota is projected to fall about 100% by 2028 — from 0.07 in 2023 to a central estimate of 0.00 (95% range 0.00–1.1). A 5-year backtest shows a typical error of ±136.2%, with 100% of held-out values landing inside the 95% band.
-100%Change by 2028
0.00Projected 2028 index
0.00–1.195% range
±136.2%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2024 | 0.01 | 0.00 | 1.1 |
| 2025 | 0.00 | 0.00 | 1.1 |
| 2026 | 0.00 | 0.00 | 1.1 |
| 2027 | 0.00 | 0.00 | 1.1 |
| 2028 | 0.00 | 0.00 | 1.1 |
Black-crowned Night Heron Survey Routes in South Dakota
| Tripp | 21 | 1999 | 1999 |
| Britton | 5 | 2021 | 1973 |
| White Lake | 4 | 2011 | 1967 |
| Veblen | 4 | 2008 | 1980 |
| Howard | 3 | 2004 | 1970 |
| Crow Creek | 3 | 2022 | 1972 |
| Wilmot | 3 | 1997 | 1967 |
| Volga | 2 | 2013 | 1968 |
| Forbes | 2 | 2023 | 1967 |
| Long Lake | 2 | 2017 | 1967 |
| Chamberlain | 1 | 1972 | 1968 |
| Raymond | 1 | 2021 | 1968 |
| Roswell | 1 | 1997 | 1969 |
| Broadland | 1 | 2013 | 2001 |
| Ft Thompson | 1 | 1998 | 1969 |
| Conde | 1 | 1968 | 1968 |
| Gettysburg | 1 | 2019 | 1972 |
| Ottumwa | 1 | 1967 | 1967 |
| Lacreek | 1 | 2014 | 1991 |
| Lane 2 | 1 | 2013 | 2012 |
Black-crowned Night Heron Population Trend in Other States
alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.