Species · Wyoming · BBS 2025 Release · 1966–2024
Black-crowned Night Heron Population Trend in Wyoming
Black-crowned Night Heron in Wyoming has collapsed: down 93% on the route-weighted index since 1979.
Notable Black-crowned Night Heron 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 →
Black-crowned Night Heron has collapsed in Wyoming: down 93% on the route-weighted index since 1979.
Black-crowned Night Heron Survey Routes 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 → | |||
|---|---|---|---|
| Harmony | 6 | 1988 | 1988 |
| Dwyer | 2 | 1992 | 1992 |
| Hunter Peak | 1 | 2003 | 2003 |
| Yellowstone | 1 | 1989 | 1989 |
| Rawlins | 1 | 1992 | 1992 |
| Rock River | 1 | 1996 | 1996 |
| Fontenelle | 1 | 2007 | 2007 |
| Elk Horn | 1 | 2000 | 2000 |
| Riverside | 1 | 1989 | 1989 |
| Buford | 1 | 2018 | 2018 |
| Yoder | 1 | 1992 | 1992 |
| Mtn View | 1 | 1989 | 1980 |
| Green River | 1 | 1982 | 1977 |
Black-crowned Night Heron Population Trend in Other States
alabamaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsin
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.