Species · Wisconsin · BBS 2025 Release · 1966–2024
Brewer's Blackbird Population Trend in Wisconsin
Brewer's Blackbird in Wisconsin has collapsed: down 84% on the route-weighted index since 1968.
-84%Since 1968
77Routes In State
58Years
Notable Brewer's Blackbird Trends in Wisconsin
long arc declinecomputed index
Brewer's Blackbird has collapsed in Wisconsin: down 84% on the route-weighted index since 1968.
Brewer's Blackbird Population Forecast in Wisconsin
If the recent trend holds, Brewer's Blackbird in Wisconsin is projected to fall about 31% by 2029 — from 0.33 in 2024 to a central estimate of 0.23 (95% range 0.00–1.8). A 5-year backtest shows a typical error of ±157.5%, with 100% of held-out values landing inside the 95% band.
-31%Change by 2029
0.23Projected 2029 index
0.00–1.895% range
±157.5%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.50 | 0.00 | 2.1 |
| 2026 | 0.43 | 0.00 | 2.0 |
| 2027 | 0.37 | 0.00 | 2.0 |
| 2028 | 0.30 | 0.00 | 1.9 |
| 2029 | 0.23 | 0.00 | 1.8 |
Brewer's Blackbird Survey Routes in Wisconsin
| Loraine | 22 | 2005 | 1966 |
| Shanagolden | 17 | 1984 | 1969 |
| Stratford | 9 | 2013 | 1968 |
| Amnicon Falls | 9 | 2018 | 1998 |
| Merrill | 8 | 2015 | 1966 |
| Stetsonville | 8 | 2024 | 1990 |
| River Falls | 7 | 2013 | 1999 |
| Irma | 6 | 2010 | 1967 |
| Manawa | 6 | 2014 | 1969 |
| Mount Horeb | 6 | 1970 | 1970 |
| Buena Vista | 6 | 2024 | 1998 |
| Cumberland | 5 | 2018 | 1967 |
| Exeland | 5 | 2023 | 1968 |
| Crandon | 5 | 2016 | 1967 |
| Viroqua | 5 | 1976 | 1976 |
| Princeton | 5 | 1993 | 1986 |
| Couderay | 4 | 2011 | 1969 |
| Holway | 4 | 1989 | 1967 |
| Gilmanton | 4 | 1988 | 1988 |
| Unity | 4 | 2023 | 1967 |
| Pardeeville | 4 | 2022 | 1968 |
| Flambeau | 4 | 2024 | 1999 |
| Cavour | 4 | 2021 | 1999 |
| Meridean | 4 | 2019 | 2002 |
| Gresham | 4 | 2011 | 1998 |
Brewer's Blackbird Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.