THE MYSTERY OF THE MONARCHS
the profoundest mysteries of the natural world is the annual trans- continental
odyssey of the Monarch butterflies from Canada, across the United States to
Mexico. Caterpillars blossoming into beautiful butterflies perform an aerial
feat of endurance and navigation without prior experience. It is their first
flight to an unknown area following something – wind, sun – yet
they reach their destination every year at precisely the same time, a feat
unique in the animal kingdom (butterflies
are animals, not insects). They start usually one at a time, then the air is
saturated with them, the startling contrast of their bright pattern immediately
process begins late on August north of Lake Huron in Canada. Tiny caterpillars
already exhibit circular bands of the monarch’s variegated colors. In an
amazing transformation they will grow and shed their skin 4 times while, within
a delicate case, a completely new being is formed. In 10 days they will lose
all traces of caterpillar and turn into a 4 winged butterfly with interconnecting
stripes: black with white polka
dots, yellow and black precisely
designed interconnecting stripes. Their wings harden in a few hours then the flight
of 100 million begins their migration. From Southern Canada, through northeast
United States, 2000 miles and two months later to Mexico.
reverse process began 3 generations earlier when a group left Mexico at the end
of winter.Then in one month they flew to the U.S. mated in Texas laying 300 – 500 fertilized eggs which
continue the journey mating and dying every month on the way until the 4th generation reaches its original starting place in Canada a full year later. The
fourth generation lives nine months and flies back to Mexico. What triggers the
annual exodus is unknown.
wingspan is 4”, its weight less than 1/5 oz. How do they survive migration?
They only fly when the conditions are perfect, when it’s too hot they stop flying,
when it’s too cold their wings become sluggish, they make infrequent stops for
nectar, their natural enemies are spider webs, bad weather like deadly
rainstorms. They fly south to avoid death of cold winter. Pesticides kill many
pf them. Decreased amount of trees in the forests and illegal logging another threat.
provides a magnetic field, and their brain cells regulate an
internal clock and keeps them on course. They must fly 50 miles per day which
requires a huge physical effort and their aerodynamic design is poor. They must
soar to conserve energy, and fly thermal winds currents like a glider.
lakes are their first trial with miles of water and shifting winds. They stop
and wait on ships’ surfaces until conditions are right, then there is the scorching desert heat, and the
Sierra Madre Mountains.
destination is 60 square miles, 10,000 feet high in Mexico
where the waiting Mexicans are celebrating “the day of the dead”. They believe the
butterflies are the spirits of their loved ones and they build alters of
flowers and fruits for them. In October they light candles and pray for their
safe arrival giving rise to
businesses in small towns the Mexicans need to survive the rest of the year. They
finally arrive the first week of November after 2 months and thousands of
miles. They fill the skies and cover
the vegetation, millions of them and there are great celebrations in the towns.
12 specific sites within the 60 miles which have perfect conditions: heat from
trees and the land while the forest supplies the umbrella. The Mexicans protect
their trees for this reason. Now they rest in clusters, clinging to the trees for
warmth for 5 months when they bloom again opening their wings to the sun. Writers
and scientists have been inspired to study them. In 1975 scientists first
discovered the extent of their migration by tagging them.
In 1992 a Monarch watch began when
Chip Taylor of the University of Kansas had kids tag the Monarchs revealing
travel speeds and flight paths. In an experiment relocating them to D.C. they still
managed to find the original flight path using different vectors to get on
track traveling through small Western towns and the Great Plains of the Southwest.
I have tried to research,
unsuccessfully, an explanation for the presence of the Monarchs on Fire Island.
They should be here as you read this. Too bad we can’t ask them. Just enjoy
this amazing phenomenon.
Monarch butterflies do migrate along Fire Island. The number of
seen at park sites last fall seemed to be less that normal, according to
one of our rangers in the field.
From the Journey North site, they have a record of 200 monarchs in a 10½
hour period on September 16, 2008:
Paula S. Valentine
Fire Island National Seashore
Images courtesy of US Fish & Wildlife Service
P.S. My research did
find this disturbing advertisement:
Special Sale! 20% off
Monarch Butterflies CLICK HERE