A flock of red-breasted mergansers was spotted around 3 p.m. just off the western shore of Promontory Point taking shelter from the wind and waves in the calmer waters.
The birds, with their teal crested heads and bright red bills, are a common sight on the Arctic coast of the Hudson Bay, but uncommon for the shores of Chicago.
The breed of diving duck does occasionally migrate past Chicago in the autumn, but it was unclear why they were here now. Ornithologists at the Field Museum, Chicago Audubon Society and other institutions were unavailable to comment on Monday.
On Monday, the group of mergansers took shelter among a cluster of goldeneye ducks, which are rarely seen in groupings of more than two.
Hyde Park’s most prominent lakefront park was transformed by the storm, its topography changed by snowdrifts and its shores transformed and extended.
The churning waves of Lake Michigan billowed with steam on the east side of the Point, where the shore was more ice than stone. Sheets of hardened snow reached out into the lake past the shore terminating in dripping stalactites of icicles.