Admirable Admirals

Found all over North America, from Mexico to Canada, the red admiral butterfly (Vanessa atalanta) has invaded New Jersey during its annual migration north.  New Jersey’s mild winter has provided the perfect conditions for the population of this butterfly to explode.  Their brown wings, splotched with red-orange bands and tipped with white spots on a black backdrop, can be found perched all over the New Jersey School of Conservation, and visitors to the school recognize the butterflies from their own hometowns elsewhere in New Jersey.

 

These butterflies are so widespread that enormous populations are migrating through western New York, Michigan, and Minnesota right now.  In fact, the butterflies can survive on almost every continent; they are found on some Caribbean islands, in Central America, New Zealand, Europe, North Africa, and Asia.  The butterflies prefer moist woods and fields, marshes, and yards and parks.  During migration, they can be found in almost any habitat, including environments as different as the subtropics and the tundra.

About every ten years, the red admiral population booms.  The last great migration of these butterflies was in 2001, so we are due for this spring treat!  Experts believe that this year’s migration is even greater than those population explosions in 2001, 1990, and 1981.  To escape the winter, red admirals fly south every year to warmer places such as the Carolinas and Georgia.  Like the monarch butterfly, the red admirals lay eggs, then die, and more are born.  In the spring, the newly born butterflies begin to migrate north, arriving in northern states like New Jersey.  Because this year’s winter was so mild, the butterflies have had better luck reproducing and creating the brilliant red and orange migrations we are seeing this spring.

Red admirals have a two to three inch wingspan.  Adults eat sap flows on trees; bird droppings; nectar from common milkweed, red clover, aster, and alfalfa; some flowers; fermenting fruit; and other plant fluids.  Adult females lay their eggs on the top of host plants, particularly plants in the nettle family.  The caterpillars, who eat the leaves of the host plant, spend their time within the shelter of folded leaves, then in a nest of leaves tied together with silk, before emerging as adults.  Like the monarch butterflies, the red admirals will produce about three generations of butterflies in the southern states before the fourth generation migrates north in the spring.  It may be another decade before these beautiful butterflies flock north in such great numbers, so be on the lookout for these admirable admirals!

References:

Hutchins, Ryan. "A Banner Year for Butterflies." The Star-Ledger 11 May 2012. Print.

"Red Admiral (Vanessa Atalanta)." Butterflies and Moths of North America. Web. 11 May 2012. http://www.butterfliesandmoths.org/species/Vanessa-atalanta.