The male red-winged blackbird, about 8 inches long with red-winged shoulders, is aggressively territorial during nesting season, which runs approximately from late May through mid-July.
Redwing Blackbirds usually nest in marshes, fields and bushes — often near lakes and ponds. They can also nest near city parks and large vacant lots, around ponds and especially along the Lake Michigan lakefront.
Male blackbird aggressiveness lasts about one month and in some reports they’ve been known to follow targets for up to 100 yards.
Redwing Blackbirds are popular at Lake Arlington, Busse Woods and Buffalo Creek near Lake Cook Road and Arlington Heights Road.
Several reports of attacks have been reported on West Grand Avenue near Rockwell Street in Chicago.