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Monarch Butterflies

Truly amazing butterflies, Monarch are likely one of the most recognized butterflies in The United States.  This is in part because of their wide distribution.  Monarch Butterflies can be found anywhere that milkweed is located.  Milkweed is the nearly exclusive food source for monarch caterpillars where as adults feed on flower nectar.  Adults will return to areas rich in milkweed in order to lay their eggs, providing a plentiful food source for their young. One little known fact about the monarch is that they feed on milkweed which contains toxins in order to store the toxin within their body which causes them to have a foul taste that in turn protects them from predators.  There bright orange, black and white wings warn predators of their poisonous, foul taste.  For this same reason, other butterfly species of similar coloration may be avoided by predators believing that they too are toxic.


Monarchs are known for their incredible mass migrations.  Up to four generations are produced throughout the year, starting at their over-wintering grounds in either Mexico or Southern California, each generation makes their way northward, with some reaching as far north as Canada.  The first three generations of the year live approximately 2-6 weeks.  Monarchs are capable of traveling 50-100 miles in a single day.  Once the fourth generation is produced, the matured adults begin their southward migration.  Adults of this generation can live upwards of nine months with their southward approximately 3,000 mile journey often takes two months to complete.  Three distinct groupings of monarchs occur within The United States, western, central and eastern.  Monarchs west of the Rocky Mountains will over-winter in Southern California while those to the east of the Rocky Mountains will migrate to winter grounds in Mexico.  Millions of monarch butterflies make the trip to the over-wintering ground in Mexico each year.


There are many current factors that continue to be a threat to the survival of the majestic monarch butterflies.  Loss of habitat in their over-wintering ranges, decreases in milkweed throughout their migratory paths as well as weather are all considerable factors in declines in monarch populations.  While adult monarchs can survive below freezing weather if they remain dry, being wet during temperature drops can cause them to freeze to death.  Occurrences of cold weather in the Sierra Nevada area of Mexico can result in devastating results for the monarch.  Monarchs are unable to fly unless their body temperature is at least 86 degrees, which results in monarchs being seen sitting in the sun or shivering their wings in an attempt to warm up prior to taking flight.  These butterflies are not injured and should be left to warm themselves.


Observers that would like to encourage monarchs to visit their home are encouraged to plant milkweed and flowers that provide nectar for adults in order to provide sustainable nutrients for the monarch.  Research groups are available to assist observers in determining the best ways to provide for the monarchs and even encourage observers in reporting their monarch activity throughout the year.