The iconic monarch butterfly may become something we can only describe in pictures to our future generations. According to a report by the World Wildlife Fund, Mexico’s Environmental Department and the National Commission for Protected Areas the annual winter migration to Central America has dropped to a record low and is in threat of ending altogether.

“I am deeply saddened by the terrible news,” Karen Oberhauser, a professor at the University of Minnesota who studies the monarchs, said by telephone at a news conference marking the release of a report. “To preserve the monarch migration, we need a groundswell of conservation.”

The annual winter migration by millions of monarch butterflies from the northern United States and Canada to central Mexico is considered by scientists and citizens alike as one of North America’s most dazzling natural phenomena. The monarch migration attracts thousands of tourists to a nature preserve about 100 miles just west of Mexico City.

The monarchs have taken over as much as 45 acres of forest in the Mexican state of Michoacan since environmentalists started 20 years ago of keeping records of where the butterflies migrate to in winter.  As of December, they covered only 1.6 acres of forest. According to records is the smallest area coverage yet.

North America offers poses many serious threats to the butterflies that didn’t once exist. For example although government conservation efforts have somewhat stymied deforestation in Michoacan, illegal logging continues to cut down oyamel fir trees, which make up the monarchs’ crucial habitat. Meanwhile herbicides for industrial-scale farming in Canada and the U.S. have destroyed the milkweed plants where the butterflies lay their eggs.

“I think it’s past time for Canada and the United States to enact measures to protect the breeding range of the monarchs, or I fear the spiral of decline will continue,” said Phil Schappert, a monarch expert in Halifax, Nova Scotia.

This is not the first time monarch butterfly numbers have been dangerously low. Monarch populations during the drought years of the 1930s “were probably as low [as] or lower than they are right now, and they recovered,” Oberhauser said. She attributes butterflies’ remarkable fertility as major reason for the monarch’s previous recovery.

That will most likely not save them this time. Oberhauser said, “the problem is that now a lot of the habitat that they had in the past is gone, due to increasing use of this land for agriculture.”