Species · Illinois · BBS 2025 Release · 1966–2024
Gray Partridge Population Trend in Illinois
Gray Partridge in Illinois has collapsed: down 96% on the route-weighted index since 1971.
-96%Since 1971
11Routes In State
24Years
Notable Gray Partridge Trends in Illinois
long arc declinecomputed index
Gray Partridge has collapsed in Illinois: down 96% on the route-weighted index since 1971.
Gray Partridge Population Forecast in Illinois
If the recent trend holds, Gray Partridge in Illinois is projected to stay roughly flat through 2015, near 0.00 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±1009.9%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2015
0.00Projected 2015 index
0.00–0.5095% range
±1009.9%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2011 | 0.00 | 0.00 | 0.50 |
| 2012 | 0.00 | 0.00 | 0.50 |
| 2013 | 0.00 | 0.00 | 0.50 |
| 2014 | 0.00 | 0.00 | 0.50 |
| 2015 | 0.00 | 0.00 | 0.50 |
Gray Partridge Survey Routes in Illinois
| Mill Creek | 4 | 1988 | 1966 |
| Guilford | 2 | 1989 | 1985 |
| Holcomb | 2 | 1993 | 1971 |
| Cherry Val | 2 | 1992 | 1972 |
| Troy Grove | 2 | 1995 | 1995 |
| Seneca | 2 | 1999 | 1993 |
| Atkinson | 2 | 1987 | 1987 |
| Geneseo | 2 | 1990 | 1988 |
| Sheffield | 1 | 1991 | 1988 |
| Compton | 1 | 1992 | 1972 |
| Newark | 1 | 2010 | 1970 |
Gray Partridge Population Trend in Other States
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.