Species · Illinois · BBS 2025 Release · 1966–2024
Hooded Merganser Population Trend in Illinois
Hooded Merganser in Illinois has collapsed: down 77% on the route-weighted index since 1994.
-77%Since 1994
18Routes In State
22Years
Notable Hooded Merganser Trends in Illinois
long arc declinecomputed index
Hooded Merganser has collapsed in Illinois: down 77% on the route-weighted index since 1994.
Hooded Merganser Population Forecast in Illinois
If the recent trend holds, Hooded Merganser in Illinois is projected to stay roughly flat through 2029, near 0.04 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±353.8%, with 100% of held-out values landing inside the 95% band.
n/aChange by 2029
0.04Projected 2029 index
0.00–0.1495% range
±353.8%Backtest error
| Year | Projected index | 95% low | 95% high |
|---|---|---|---|
| 2025 | 0.04 | 0.00 | 0.14 |
| 2026 | 0.04 | 0.00 | 0.14 |
| 2027 | 0.04 | 0.00 | 0.14 |
| 2028 | 0.04 | 0.00 | 0.14 |
| 2029 | 0.04 | 0.00 | 0.14 |
Hooded Merganser Survey Routes in Illinois
| Cameron | 6 | 1989 | 1989 |
| Beaverdam Lk | 5 | 1995 | 1970 |
| Troy Grove | 4 | 2018 | 2018 |
| Camp Point | 3 | 2011 | 2011 |
| Concord West | 2 | 2010 | 2010 |
| Newark | 2 | 2010 | 2010 |
| Gulfport | 2 | 2014 | 2013 |
| Seneca | 1 | 2024 | 2015 |
| Payson | 1 | 2016 | 2016 |
| Pawnee | 1 | 1998 | 1994 |
| Kell | 1 | 2006 | 2006 |
| Jamestown | 1 | 2012 | 2004 |
| Beaucoup | 1 | 2012 | 2011 |
| Grape Creek | 1 | 2022 | 2004 |
| Olney | 1 | 2017 | 2017 |
| Pulaski | 1 | 1996 | 1996 |
| Dudleyville | 1 | 2010 | 2010 |
| Minonk | 1 | 2004 | 2004 |
Hooded Merganser Population Trend in Other States
alabamaalaskaarkansascoloradoconnecticutidahoindianaiowakansaskentuckymainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanew-hampshirenew-yorknorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontwashingtonwest-virginiawisconsinwyoming
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.