EDITOR'S NOTE: Digital photo available on request,(864) 656-3876.

DATE:   8/24/00 
WRITER: Dr. Joe Culin, (864)656-5041
EDITOR: Giles Singleton, (864) 656-3876
                                
The Monarchs are coming!
                                
     CLEMSON --  If you are a butterfly watcher, it's time to 
move the lawn chair to the garden and get ready for the show. 
Why? In most of South Carolina, masses of Monarch butterflies 
should begin to arrive any day. These regal black and orange
butterflies will remain with us through September or early 
October before continuing their migration to central Mexico.
     Many people recognize Monarch butterflies due to the 
large numbers that are often present, their distinctive color 
pattern and their large size - a Monarch has a wingspan of 
three to four inches. The Monarch is a common late summer 
and fall visitor to South Carolina gardens, where it feeds 
on nectar to fuel its continued migration flight.
     The Monarch is the only true migrating butterfly 
that occurs in North America. To be a true migrant, the 
same individuals must travel from one geographic region 
to another, spend some time there, and then return to the
original area.
     In South Carolina, we are fortunate to have three major 
southern flyways cross the state. One runs in the mountains 
through the Whitewater and Seneca river watersheds -- now 
lakes Jocassee, Keowee, & Hartwell -- another follows the 
"ridge" along the sandhills, and the third runs along the 
coast. 
     In some years, I have seen hundreds of Monarchs each 
hour flowing over Whitewater falls and spilling out on to 
Lake Jocassee. 
     However, the numbers of Monarchs in each of these 
flyways can vary considerably, depending on the track 
followed by southerly moving weather systems.
     For example, in years when hurricanes or strong tropical 
storms approach the southern coast in August or September, 
the counterclockwise winds can result in a strong western 
shift of the flyways. This happened in 1998 when hurricanes 
Bonnie, in August, Georges, in September, and Mitch, in 
October, pushed most of the migrating Monarchs over to the 
midwestern flyways. That year, very few Monarchs were seen 
in South Carolina.
     Although we occasionally see Monarchs in the spring, 
these are generally few and far between. Like the occasional 
western shift of southerly migration routes due to storms, a 
strong storm at the right time can shift some north-bound 
spring migrants our way.
     In North America, there are two geographically distinct 
Monarch populations, separated by the Rocky Mountains.  In 
the eastern population, Monarch butterflies and caterpillars 
are common summer sights on and around milkweed plants from 
the Great Plains to the East Coast and from Mexico into
Canada. The only region not occupied during the summer is 
the Southeast -- South Carolina, Georgia, Florida and 
Alabama -- because our native milkweed plants are not suitable 
food for the Monarch caterpillars.
     After they spend several generations in the Midwest and 
Northeast, the shorter days and cooler temperatures of late 
summer begin to trigger the Monarchs' migratory behavior.
     Migratory butterflies are much more active than non-
migratory ones. They will regularly take flight in large 
numbers, with groups often flying hundreds of feet up into 
the sky. This activity increases as southerly moving storm
fronts approach areas where Monarchs are present. 
     When both migratory activity and weather patterns come 
together, thousands, and sometimes hundreds of thousands, 
of Monarchs will fly up into the fast moving frontal winds 
pushed ahead of these weather systems. Once airborne, the 
Monarchs ride these winds, much like a surfer rides a wave, 
as they undertake their journey to the mountain sites in 
central Mexico, where they will spend the winter. These 
mountain locations provide the environmental conditions 
that allow the millions of Monarchs that have traveled 
from as far away as Eastern Canada to survive the winter.
     As temperatures in the Mexican mountains warm in the 
spring, the butterflies become active and begin to take 
short flights and feed from early spring flowers. By March 
or April they leave the overwintering sites and begin the 
last phase of their migration, which takes them back into 
Texas and the western Gulf Coast. There the migrants lay 
their eggs on milkweeds and eventually die as a new 
generation of caterpillars hatch. 
     When these caterpillars become butterflies, they will 
disperse into the Midwest and Northeast by riding northerly 
moving spring frontal winds that carry them up the Mississippi 
River Valley.
     More information on Monarch biology and migration can 
be found on the Monarch Watch web site at HTTP://MONARCHWATCH.ORG.
-- Joe Culin, Clemson Extension specialist and chair of Clemson's Department of Entomology.
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     If you have questions or comments on gardening, write 
to PSA Media Relations, A-101 Poole Agricultural Center, 
Clemson University, Clemson, S.C. 29634-0129.
     You might also want to look for other "Buds and Blooms" 
columns under 2000 News Releases at: www.clemson.edu/psamedia .
                            END