The Monarch butterfly is perhaps the most well-known and best-loved insect in North America. Even people who are squeamish around “bugs” are delighted when they see a group of Monarchs flying across a field. In order to determine when you should begin to watch for Monarchs in your area, it is important to have a basic understanding of the life cycle of these amazing little creatures and what drives them to migrate.
Monarchs that emerge out of their chrysalis in summer are different from Monarchs that emerge in the fall. Summer Monarchs will mate and lay eggs in the warm months, but fall Monarchs immediately prepare for flight to avoid the cold weather season and have a different biological clock, returning to the area they emerged in the spring season to mate and lay their eggs. They prepare for migration by storing fat from nectar in their abdomens.
Monarch butterflies spend their winter in what is known as “roosting spots” in warmer locations as they are unable to survive colder seasons. North American Monarchs are known for their long migration with some traveling as much as three thousand miles. In fact, they are the only species of butterfly on the planet to make such a long journey.
The Monarch’s migration is similar to annual bird migrations and occurs according to seasonal changes, such as temperature fluctuations, and day length. Some groups of Monarchs will return to the same exact trees each year, with their great-great-grandchildren coming in their place the next year. How they know where to return is somewhat of a mystery, even to researchers. You can determine when the Monarchs will migrate through your area, or return if you live in an area where they mate and lay eggs, simply by watching for changes to local weather patterns.