The Monarch butterfly (scientific name: Danaus plexippus) is perhaps the best known of all North American butterflies. It is easily recognizable by its bright orange-red wings, with black veins and white spots along the edges. The Monarch butterfly is famous for its southward migration from Canada to Mexico and the northward return back to Canada in summer. Every fall, millions of these butterflies fly west to their wintering grounds in California and Mexico, covering the trees there with their bright shimmering wings. These butterflies congregate into colonies, clustering onto the pine and oyamel trees. In many cases, they are so thick that the trees turn orange in color and branches sag from the weight. It?s a remarkable sight that attracts scores of tourists.
The Monarchs are the only butterfly that migrates both north and south as the birds do regularly, but no individual makes the entire round trip, because the migration period spans the life of three to four generations of the butterfly. Monarch butterflies are also one of the few insects which can cross the Atlantic.