Monarch butterfly (Danaus plexippus) is a milkweed butterfly. Perhaps the best known of all North American butterflies. Since the 19th century it has been found in New Zealand and Australia since 1871 where it is called the Wanderer. In Europe it is resident in the Canary Islands, the Azores, and Madeira, and an occasional migrant in Western Europe. Wingspan of 3.5-4 in. (8.9–10.2cm). Monarch is famous for its southward migration and northward return in summer from Canada to Mexico and Baja California which spans the life of three to four generations of the butterfly. Santa Barbara County, CA.