Species · Illinois · BBS 2025 Release · 1966–2024
Black-billed Cuckoo Population Trend in Illinois
Black-billed Cuckoo in Illinois has collapsed: down 91% on the route-weighted index since 1968.
-91%Since 1968
62Routes In State
55Years
Notable Black-billed Cuckoo Trends in Illinois
long arc declinecomputed index
Black-billed Cuckoo has collapsed in Illinois: down 91% on the route-weighted index since 1968.
Black-billed Cuckoo Population Forecast in Illinois
If the recent trend holds, Black-billed Cuckoo in Illinois is projected to stay roughly flat through 2028, near 0.00 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±309.4%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2028
0.00Projected 2028 index
0.00–0.2595% range
±309.4%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2024 | 0.00 | 0.00 | 0.25 |
| 2025 | 0.00 | 0.00 | 0.25 |
| 2026 | 0.00 | 0.00 | 0.25 |
| 2027 | 0.00 | 0.00 | 0.25 |
| 2028 | 0.00 | 0.00 | 0.25 |
Black-billed Cuckoo Survey Routes in Illinois
| Guilford | 4 | 2023 | 1973 |
| Holcomb | 3 | 2008 | 1972 |
| Geneseo | 3 | 2013 | 1967 |
| Compton | 3 | 1973 | 1973 |
| Mill Creek | 2 | 2007 | 1966 |
| Putnam | 2 | 1990 | 1990 |
| Chandlervill | 2 | 1973 | 1972 |
| Deer Creek | 2 | 1997 | 1978 |
| Milford | 2 | 2007 | 1970 |
| Concord | 2 | 2011 | 1967 |
| Rosamond | 2 | 1978 | 1978 |
| Grape Creek | 2 | 2019 | 2019 |
| Caledonia | 2 | 2016 | 1993 |
| Seneca | 2 | 2021 | 2021 |
| Cherry Val | 1 | 1993 | 1973 |
| Barrington | 1 | 1991 | 1972 |
| Atkinson | 1 | 1989 | 1982 |
| Sheffield | 1 | 2004 | 1966 |
| Buda | 1 | 1991 | 1977 |
| Streator | 1 | 1992 | 1972 |
| Wayne | 1 | 1997 | 1975 |
| Newark | 1 | 1990 | 1990 |
| Sherburnvill | 1 | 2019 | 1979 |
| New Lenox | 1 | 1991 | 1966 |
| Gulfport | 1 | 1991 | 1982 |
Black-billed Cuckoo Population Trend in Other States
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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.