As the days begin to grow shorter following the Fall Equinox in North America, migrating monarch butterflies set out on their long journey ~ as far as 2,000 miles ~ to escape the cold of Winter. They are the only butterflies to regularly migrate both north and south as birds do.
The length of their journeys exceeds the normal lifespan of most monarchs, which is less than two months for butterflies born in early Summer. The last generation of Summer enters into a non-reproductive phase known as diapause and may live seven months or more. During diapause, butterflies east and west of the Rockies fly to one of many overwintering sites.
Click on map to animate
Some west of the Rockies find sanctuary in the sheltered eucalyptus grove at Natural Bridges State Park in Santa Cruz, California. When temperatures in its canyon rise above 55 degrees, butterflies leave their warm, protective clusters in the eucalyptus trees in search of flower nectar and water.
The overwintering generation generally does not reproduce until it leaves the site sometime in February and March. Mating occurs in Spring, just prior to their northern migration. Monarchs travel only as far north as they need to go to find the early milkweed growth to lay their eggs.
The monarch metamorphizes through four radically different stages before becoming an adult: egg; caterpillar, chrysalis; and butterfly – then typically lives two to eight weeks in gardens, fields, prairie, parks, and roadsides that offer sufficient nourishment.
Depending upon their destiny ~ whether they were born early or late in the season ~ monarchs are hearty creatures with an awesome (yet still not fully understood) sense of direction. While viewing this clip, I invite you to contemplate the mystery of butterfly migration and the fleeting beauty monarchs bring us each year when they return.
Monarch Butterflies from viktoriavidali on Vimeo.
For additional information, visit Friends of Santa Cruz State Parks.
If you enjoyed this post, you might also like to read In Search of Monarchs and view The Beauty of Pollination.
