Environmental Almanac writer Rob Kanter consulted retired INHS Entomologist Mike Jeffords to find out why central Illinois has been inundated with red admiral butterflies. According to Jeffords, the red admirals we see in spring are migrants that overwintered to the south and the few that survived the winter here. This year the mild winter allowed greater survival and the subsequent swarms of red admirals. Jeffords, along with Susan Post (another retired INHS Entomologist) have found that other butterflies are active and numerous earlier than usual this spring. They reported seeing 22 species of Illinois butterflies before April, which is twice their usual number.
