Based on 3,518 research-grade iNaturalist observations in Illinois, Red-breasted Merganser is most often recorded in March; in Illinois it behaves like a winter visitor. It ranks #38 among birds recorded in the state in our data.
Mergus serrator
Red-breasted Merganser in Illinois by month
Bars show research-grade observations per month. They mix true seasonality with how often people are outdoors, so treat small numbers with caution.
Also seen in Illinois in March
American Robin
Canada Goose
Mallard
Northern Cardinal
Red-winged Blackbird
House Sparrow
Dark-eyed Junco
Song Sparrow
Places to look in Illinois
State ParkCahokia
Botanical GardenMorton Arboretum
National ForestShawnee National Forest
Botanical GardenChicago Botanic Garden
Botanical GardenLadd Arboretum
State ParkStarved Rock State Park
FAQ
When does Red-breasted Merganser appear in Illinois?
Mainly December–April, with the most records in March.
How common is Red-breasted Merganser in Illinois?
It ranks #38 by number of iNaturalist observations among birds in Illinois (3,518 records in our sample).