The range of the western and eastern populations of the monarch butterfly expands and contracts depending upon the season. The range differs between breeding areas, migration routes, and winter roosts.
In North America, the monarch ranges from southern Canada through northern South America. It has also been found in Bermuda, Cook Islands, Hawaii, Cuba and other Caribbean islands the Solomons, New Caledonia, New Zealand, Papua New Guinea, Australia, New Guinea, Sri Lanka, India, Nepal, the Azores, the Canary Islands, South Africa, Gibraltar, Philippines, North Africa[21] and Honolulu. It appears in the UK in some years as an accidental migrant. No genetic differences between monarch populations exist. Reproductive isolation has not created subspecies.
Overwintering populations of D. plexippus are found in Mexico, California, along the Gulf coast, year-round in Florida, and in Arizona where the habitat has the specific conditions necessary for their survival. Their overwintering habitat typically provides access to streams, plenty of sunlight (enabling body temperatures that allow flight), and appropriate roosting vegetation, and is relatively free of predators. Overwintering, roosting butterflies have been seen on basswoods, elms, sumacs, locusts, oaks, osage-oranges, mulberries, pecans, willows, cottonwoods, and mesquites. While breeding, monarch habitats can be found in agricultural fields, pasture land, prairie remnants, urban and suburban residential areas, gardens, trees, and roadsides – anywhere where there is access to larval host plants. Habitat restoration is a primary goal in monarch conservation efforts. Habitat requirements change during migration. During the fall migration, butterflies must have access to nectar-producing plants. During the spring migration, butterflies must have access to larval food plants and nectar plants.
