Monarch Migration Patterns

In 1937, Scientist Fred Urquhart and his wife, Norah, tagged thousands of monarchs by gluing paper tags to their wings and releasing them.  The tags requested that anyone finding them please send them back to the Zoology Department at the University of Toronto, Canada.  In 1975, two of their colleagues, Cathy and Ken Brugger, of Mexico City located a wintering site of the monarchs.  Tens of millions of monarchs have been viewed in the Sierra Madre Mountains of Mexico.  There are 12 known areas of forest in Mexico where monarchs gather for the winter.  These locations are at around 9,000 feet in elevation and are generally cold.  Monarchs east of the Rockies tend to winter in Mexico while those west of the range winter along the California coast.   

Amazingly, monarchs in North America travel up to three thousand miles which is farther than all other tropical butterflies!  While this type of migration is similar to birds or whales, it is unique in that their future generations return south the following fall to roost for winter.  Each season, there are four generations of monarchs that begin to journey north.  The final fourth generation, known as the super generation, live longer and fly farther than all previous generations.  Scientists believe this is due to cooler temperatures and their lack of needing to reproduce before wintering.  Here in Florida, we typically see migrations through our state in March to April and again in October to November.  Some monarchs will also winter in the southern part of Florida due to the warm, tropical year-round temperatures.  It is clear that monarchs are highly resilient considering their need to find milkweed to lay eggs on, that predators seek them, and that environmental factors can threaten their survival.  Their life cycle and migration is a truly impressive feat!