The monarch butterfly—a treasured visitor to gardens across America—was officially designated an endangered species Wednesday. Known for its epic biannual migration spanning 2,500 miles across the continent between its summer and winter grounds, the numbers of monarchs of the butterflies have plummeted by between 23 and 72 percent in the last 10 years, according to the International Union for the Conservation of Nature (IUCN). By joining the organization’s Red List, this is the first time the monarch butterfly has been officially recognized as being at risk of extinction. “It’s hard for people to imagine that something that shows up in their backyard is threatened,” Anna Walker, who led the monarch butterfly assessment, told National Geographic.