Species · Illinois · BBS 2025 Release · 1966–2024
Yellow-billed Cuckoo Population Trend in Illinois
Yellow-billed Cuckoo in Illinois has declined: down 29% on the route-weighted index since 1968.
-29%Since 1968
100Routes In State
58Years
Notable Yellow-billed Cuckoo Trends in Illinois
No notable trend signals for Yellow-billed Cuckoo in Illinois. See the full index history below.
Yellow-billed Cuckoo Population Forecast in Illinois
If the recent trend holds, Yellow-billed Cuckoo in Illinois is projected to fall about 43% by 2029 — from 2.5 in 2024 to a central estimate of 1.4 (95% range 0.00–3.8). A 5-year backtest shows a typical error of ±25.1%, with 100% of held-out values landing inside the 95% band.
-43%Change by 2029
1.4Projected 2029 index
0.00–3.895% range
±25.1%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 1.7 | 0.00 | 4.0 |
| 2026 | 1.6 | 0.00 | 4.0 |
| 2027 | 1.5 | 0.00 | 3.9 |
| 2028 | 1.5 | 0.00 | 3.8 |
| 2029 | 1.4 | 0.00 | 3.8 |
Yellow-billed Cuckoo Survey Routes in Illinois
| Belknap | 21 | 2024 | 1970 |
| Belleview | 20 | 2024 | 1966 |
| Pulaski | 15 | 2024 | 1970 |
| Mascoutah Lk | 14 | 2024 | 1967 |
| Delwood | 11 | 2024 | 1970 |
| Royalton | 10 | 2024 | 2001 |
| Beaverdam Lk | 9 | 2023 | 1970 |
| Cave In Rock | 8 | 2024 | 1993 |
| Duncan Mills | 7 | 2024 | 1993 |
| Eldred | 7 | 2021 | 1993 |
| Eubanks | 7 | 2024 | 2002 |
| Mt Vernon | 6 | 2024 | 1971 |
| York | 6 | 2024 | 1993 |
| Sandusky | 6 | 2023 | 1993 |
| Karnak | 6 | 2024 | 2001 |
| Putnam | 5 | 2022 | 1967 |
| Bluff Spgs | 5 | 2024 | 1967 |
| Bremen | 5 | 2024 | 1969 |
| Yale | 5 | 2024 | 1993 |
| Bradbury | 4 | 2024 | 1970 |
| St Morgan | 4 | 2022 | 1967 |
| Lake Summerset | 4 | 2019 | 2003 |
| Clayton | 4 | 2021 | 2001 |
| Kell | 4 | 2024 | 2001 |
| Sheffield | 3 | 2022 | 1966 |
Yellow-billed Cuckoo Population Trend in Other States
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Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.