Dan's Papers - October 6, 2006

On September seventeenth, a teacher in East Moriches counted over one hundred Monarch butterflies flying through the sky above her head. This sighting confirms that the Monarchs have begun their treacherous and exciting annual journey from Canada to the pine forests of Mexico. Lucky for us, the Hamptons are one of the many stops they will make along the way!

The Monarchs' flight path follows the milkweed plant, which grows in specific places across North America. Milkweed is the Monarch's favorite food, resting place and nursery, so it is important that Monarchs find milkweed plants wherever they go. One journey from Canada to Mexico can be as long as 3,100 miles, and the Monarchs must travel an average of fifty miles per day in order to get to Mexico before winter. Monarchs encounter all sorts of danger on their trip, from rainstorms and freezing cold weather to speeding cars and exhaustion. Many butterflies do not make it through an entire journey, and only a few have been able to make the complete loop to Mexico and back. Luckily, the butterflies' entire life cycle only takes six weeks from egg to butterfly, so in the spring many young Monarchs join the migration their parents and grandparents began months before, flying to a place they have never been. One Monarch, tagged by Donald A. Davis in Ontario, Canada, in 1988, was found flying in Austin, Texas in 1989; that means that not only did he make it all the way from Canada to Mexico, but that he also made it half of the way back the next year.

When the butterflies migrate to Mexico in the fall, they concentrate on getting south as quickly as possible, but when they fly from Mexico to Canada in the spring, the butterflies stop to mate and lay eggs along the way.

Monarchs will only lay their eggs on Milkweed plants, which are poisonous to many species of animal, to protect the eggs from being eaten by mistake. In about two weeks, the yellow, black and white striped caterpillars are born. They eat so much Milkweed that their bodies absorb the plant's toxins and the caterpillars become poisonous themselves. Their predators know that they are poisonous because of their bright colors; most brightly colored insects are either poisonous or taste terrible. After two weeks of being a caterpillar, the baby Monarchs hang upside-down to make their pupas, also known as a cocoons or chrysalis. It only takes a baby Monarch a few hours to build the bright green chrysalis where they will spend the next couple of weeks transforming into a beautiful Monarch butterfly. Once the adult butterfly hatches, it hangs onto the empty cocoon and fills the veins in its wings with blood that it has stored in its body for just this purpose. When its wings are fully inflated, the butterfly flies away to begin its journey north for the summer.

Once the young Monarch hatches, it will join its parents and grandparents on their journey North, spend the summer in Canada, and then start flying South, eventually landing on the East End for a rest along the way.

If you see any migrating Monarchs this week, watch them closely. Monarch butterflies cannot fly when the temperature drops below 55 degrees, which is why they are diurnal (they sleep at night and fly during the day). In order for them to fly quickly and easily, however, their bodies must be significantly warmer than the air. In September, most butterflies you see are either basking in the sun with their wings open or shivering to keep warm. Just like shivering raises our bodies' temperatures by creating heat through movement, shivering raises the butterflies' bodies' temperatures, too. And the deep orange color of their wings and dark black lines attract and hold heat from the sun, which gives them enough energy to fly in the cooler East End weather. By November, the Monarchs will begin to arrive in the pine forests of Oyamel, Mexico, where they will rest and eat all winter long, preparing for their journey north.

If you would like to learn more about this year's Monarch migration, and track their progress from Canada to Mexico, visit www.learner.org/jnorth/fall2006.