Butterflies, too, take wing twice a year
A note last week from local birder Nic Korte detailing some of his recent winged discoveries around the Mesa/Collbran area also included this: “The most striking sightings were (approximately) two dozen migrating monarch butterflies at Mogensen Ponds.”
It’s a reminder to casual nature watchers that birds aren’t the only species to take wing twice a year.
Monarch butterflies are known for their migrating abilities, with those east of the Rocky Mountains and along the East Coast generally headed about 2,500 miles to specific oak trees in the Transvolcanic mountains of south-central Mexico.
Those west of the Continental Divide, including those seen by Korte near Mesa, head for the eucalyptus trees around Pacific Grove, Calif.
What might be most curious about butterfly migrations is that unlike birds, elk or deer, the butterflies migrating this fall are the great-great-grandchildren of those doing the spring migration.
According to the website http://www.monarch-butterfly.com, the year’s first three generations of Monarch butterflies live about six weeks after hatching from their cocoons.
It’s the fourth generation that lives for up to eight months, enabling those insects to migrate to a warmer climate, hibernate, then start the next first generation in the spring.
Which begs the question of how these new-generation butterflies know how and where to migrate.
No one yet knows how the monarch butterfly’s homing system works.
However, solving the puzzle of the monarch migration has inspired a program called Monarch Watch at the University of Kansas.
The program enlists hundreds of volunteers across central and eastern North America for capturing, tagging and releasing monarchs during the fall migration, hoping to reveal keys to the migration.
More monarch facts:
■ Female monarch butterflies lay several hundred eggs each spring.
■ Monarch caterpillars need milkweed to live and grow, but recent declines in milkweed (weed abatement and development) have cut into the monarch population.
■ Monarch butterflies go through four life stages. They start as an egg, hatch into larvae (a caterpillar), then wrap up in the cocoon (pupa or chrysalis). It’s in the cocoon where they change into a butterfly.
■ An adult monarch can eat nectar from any flower, not just the milkweed plant. Only the caterpillars need the milkweed plant to live.
■ Monarch butterflies are poisonous. Not to humans, but they secrete chemicals absorbed from the milkweed, which gives the butterfly a poisonous defense against predators such as frogs, birds, mice and lizards.
■ You actually can differentiate between a male and female monarch: Male monarchs have a black spot on a vein on each hind wing; the females do not.