As monarch butterflies are beginning their epic migration from Canada and the U.S. to Mexico for the winter, concerns about the drastic rate at which they’re disappearing from the landscape have led environmental and health organizations to petition the government for federal protection.

This week, the Center for Biological Diversity, Center for Food Safety, Xerces Society and monarch scientist Dr. Lincoln Brower filed a legal petition with the U.S. Fish and Wildlife Service seeking protection for monarchs under the Endangered Species Act.