Migration of the Monarch Butterfly

The yearly autumn mass migration of the North American Monarch Butterfly (Danaus plexippus), starting in September and October of each year, is a truly amazing phenomenon!

Did you know that the Monarch Butterflies of North America can migrate up to 3000 miles?

It’s hard to imagine that something as delicate-looking as a butterfly can travel that far, but some North American monarchs migrate very long distances, as far as from Canada to Central Mexico.

Monarchs are one of the most widely recognized butterflies in North America, but they can also be found in South America, parts of Australia and New Zealand, and occasionally in a few areas of Europe. Only the North American monarch butterfly migrates any great distance.

In fact, the migration of the monarch butterfly is the largest and longest migration of any North American insect. But the individuals who migrate south for the winter only make this trip once. The group of monarchs that fly south the next year are the fourth generation after the previous year’s migration.

The Monarch butterfly (Danaus plexippus) is a milkweed butterfly (subfamily Danainae), in the family Nymphalidae. It is perhaps the best known of all North American butterflies. Since the 19th century, it has been found in New Zealand, and in Australia since 1871 where it is called the Wanderer. It is resident in the Canary Islands, the Azores, and Madeira, and is found as an occasional migrant in Western Europe and a rare migrant in the United Kingdom. Its wings feature an easily recognizable orange and black pattern, with a wingspan of 8.9–10.2 centimetres (3½–4 in). (The Viceroy butterfly is similar in color and pattern, but is markedly smaller and have an extra black stripe across the hind wing.)

Female Monarchs have darker veins on their wings, and the males have a spot called the “androconium” in the center of each hind wing from which pheromones are released. Males are also slightly larger.

Each winter, 20 million monarch butterflies from Canada come to the Mexican state of Michoacan, seeking the perfect combination of fir trees, food, and temperature at over 10,000 feet to breed and feed before flying north. This particular February day 2009, the sun was shining, which led to a lot of activity in the air.

The 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.