Monarch butterflies are coming back. Each year, the butterflies make a  3,400 miles round trip.They fly from United States to Canada and then to Mexico.They spend winters on a mountain located  west of Mexico City.  This year 140 million monarchs may come. The monarch butterflies have a beautiful white and orange pattern on their wings. The western north american population of monarchs west of the Rocky mountains often migrates to sites in southern california but have been found in Mexican sites as well.