Every year millions of Monarch butterflies migrate from Mexico to Canada. There are many tremendous venues that host the Monarch butterfly (Danaus plexippus) in their route during their migration every year from October to March. Population of this magnificent aphid has gone down over the years. During their migration, you could see them fluttering all around the branches of the plants and trees. They form these clusters in branches to keep them warm for the evening. There are 3 superb images of the migration of the Monarch Butterfly.