A Monarch butterfly is the most famous American butterfly that is identified via its wings of orange and black color pattern. There is one more feature that sets it apart from the other butterflies, its unusual behavior of migration for escaping winter. Taking place annually in September and October, the Monarch butterfly migration is genuinely an incredible phenomenon. Well, you will be surprised to know that these butterflies of North America have the stamina of traveling up to 3000 miles. I know it is not that easy to imagine this capability for a delicate-looking insect, but this holds naturally true for the North American monarchs who travel from Canada to Central Mexico just to avoid staying in its native habitat’s freezing temperatures. Besides North America, these are also seen in South America, New Zealand, Australia, and Europe.
The Monarch butterfly migration is regarded as the longest as well as largest journey of a North American insect. There are two directions in which these Monarchs migrate. One is towards the South for running away from the cold and the next is towards North in order to look for food. Biologically, it has been found that these butterflies along with their pupae (chrysalises) as well as larvae (caterpillars) cannot survive in the very cold winter that is peculiar to the northern climate. This is the reason why the Monarch butterfly migration in Mexico takes place towards south just for survival. This unusual behavior is not seen in the monarchs that live in other parts of the world, as there the winters are not so harsh and so they only travel for some very short distances if they feel the need to do so. On the same lines, other insect as well as butterfly species along with the pupae, larvae, and some adults can live in chilling climates avoiding the need to migrate. Now, your question would be – why these monarchs have to migrate every year? Why do they not stay in south only? Well, the monarch larvae only nourish on milkweed plants that grow only in those zones where the adults do not overwinter. So, milkweeds are seen in plenty in the north and so the adults need to fly for laying their eggs.
The Monarch butterfly migration in Mexico has two areas as its destination. One is Western North America and the other is the Central as well as Eastern North America. In case of the former, the monarchs living in the west of the Rockies travel until the California’s south coast next to San Diego and Santa Cruz. This is where these butterflies settle in the trees of Eucalyptus, Monterey cypresses, and Monterey pines. On the other hand in the latter case, millions of Monarchs living in the east of the Canadian Rockies as well as in the United States migrate annually in Mexico directing themselves via Texas until the Central Mexico Mountains where they rest in the Oyamel forests of fir that are above 2 miles from the sea level. Both in Mexico and California, these butterflies assemble as dense bunches for remaining warm. In fact, several of thousand butterflies rest on a single Oyamel fir tree. Looking at this phenomenon and with the aim of protecting these beautiful species, the Mexican government declared this area has the Mariposa Monarca Biosphere Reserve.
The Monarchs that migrate to the Gulf of Mexico travel continuously along the coastline in a southwest direction until they settle down in the Transvolcanic Plateau of Mexico. Here, some 300 million Monarchs live during the winter. While they are migrating, many dangers come in their way such as predators, storms, fatigue, and humans or cars. Sadly, several of them die in tornado, become the prey of the birds, or get crushed by the cars. The danger to their life continues even if they have safely reached at their retreats in winter. Especially in Mexico, the risk of storm is higher along with heavy snow and strong winds killing countless.
The Monarch butterfly migration route is yet to be completely known. However, what is known is as follows: August to September: Living the mid-central America, September to November: South migration, March: North migration starts, April and June: Many migrate in north, June and July: End of migration. During the migration, the butterflies feed on flowers widely for seeking the nectar’s carbohydrates that give them the energy to travel by building the fat in the abdomen making them to cover over 50 miles daily at 12 miles per hour. While clustering at their roosting site in large numbers on the trunks as well as branches of the Oyamel trees, they stay very inactive. Somewhere in February, they turn out to be the most active and begin to mate. At the month’s end, a few start migrating northward pulling others depleting the luster scene by mid-March. This is the spring migration carrying only 50% of the roosting population to their homes in north. This is because nearly 40% Monarchs die while in Mexico. If you cannot come to Mexico, try planting the milkweed plants in your garden to see this scenery.