Every Autumn a small miracle occurs. As the leaves turn brilliant shades of red, gold, and orange and equally splendidly colored creature, the Monarch butterfly, prepares for a long journey. How dows a creature no more than four inches across make a cross continent trek from North America to Centeral Mexico?

For years scientists and others have found it amazing that birds manage a similar journey, but a small, delicate insect? Many scientists refused to believe such a feat possible. For years the Monarchs annual disappearance was thought to be explained by hibernation habits much like the hibernation behavior practiced by the mourning cloak butterfly. It seemed a logical assumption, after all, as the mourning cloak manages to survive in such extreme habitats such as Alaska. Maybe the Monarch went about survvng cold harsh norther winters in a similar manner.

Thanks to the tireless work of entomologist Fred Urquhart, his wife, Nora Urquhart, and the work of countless volunteers, especially Ken and Cathy Brugger, this belief was laid to rest on Jauary 2, 1975. The Brugger's determination to find the Monarch wintering site payed off. In the Fall of 1974 the Urquharts hired the Bruggers to hunt for the butterflies full time. Despite the threats of local landowners, who thoght the Bruggers weere looking for treasure, and who threatend to shoot them, the Bruggers continued their exhaustive search. On January 2, 1975 the Bruggers discovered tens of millions of Monarchs resting on trees on the mountain Cerro Pelon.(Zimmer, 38) Up to four million butterflies can occupy one acre! (Malcolm & Zalucki)

This discovery forever changed the way in which the annual vanishing of the Monarchs was viewed. Instead of dispelling the mystery, however, this only served to futher enhance the mystery of the migration. How do the Monarchs know where to go? They have no older Monarchs to show them the way as birds often have elders who have made the trip before. How do the Monarchs know when it is time to go?

Lincoln Bower, a leading monarch expert at the University of Florida and with Wildlife Conservation International, thinks that the monarchs us magnetic fields to navigate. They carry crystals of magnetic minerals in their bodies. He believes that the monarchs posess a kind of compass which helps to guide them to their destination. He hypothesizes that the changing length of daylight is what sets the biological compass heading and is preparing to do an experiment to prove this theory. He wants to raise Monarch butterflies under different patterns of light. Whent he time comes to set them free, they should fly away in their different "predetermined" directions (Zimmer, 39)

When the Monarchs migrate they fly at speeds of up to 30mph and at an altitude of up to a mile. They travel as much as 2,00 miles. (Monarchs who live west of the Rocky Mountains fly to Souther California) and congregate on thirty sites located in a 40 mile stretch of mountains just west of Mexico City. The form their colonies between altitudes of 2300 and 3100m. At this altitude temperatures are stable more often than not. A balance of moisture and temperature seems well suited to the needs of the wintering monarchs. However, upon occasion the weather becomes quite nasty. Snow storms have occurred almost every year since the Monarch wintering sites were discovered. This poses another interesting question. Hw does an insect, which is cold blodded, survive freezing temperatures?

The answer most likely lies in the monarchs posessing some sort of freeze protection mechanism. There are two means that insects use to survive being exposed to freezing temperatuires. The first is by tolerating ice within their cells or directing ice away from intracellular tissues with extracellular nucleating agents. Most insects can avoid being frozen by other means, by possessing concentrations of antifreeze biochemicals, which, of course, helps keep ice from forming in their systems. These chemicals function in three ways: (1) by lowering the freezing point of the body fluids, (2) by lowering the supercooling point of the body fluids, 3) by inhibiting the growth of ice crystals withing the body, producing an effect which is know as "thermal hysteresis"

Monarch Butterflies do some amazing things in order to survive and reproduce. They survive freezing temperatures, snow storms, predators, cross continent journeys, man-made obstacles such as cities, lakes, streams and rivers, but perhaps there is one thing they will not be able to survive. Alarmingly, the forests in which they spend their winters have been degraded by logging and cattle ranching for decades. If efforts are not made to preserve these forests, then entire species of migrating monarchs could possibly become yet another beautiful but extinct wonder of the past.