Butterfly Season

(Photo: Butterflies at the Pacific Grove Monarch Butterfly Reserve courtesy of the owner.) © Adam R. Paul)

When Pacific Grove school children parade through the streets this weekend to welcome monarch butterflies back for the winter, they won't be welcoming the same ones that were here last year. This year's monarchs will be the great-grandchildren of the ones that left in February and March. While the wintering generation lives six to eight months – feeding, riding trade winds and mating -- the four or five generations in between live only three to six weeks each. There is much mystery in it, and the Ventana Wildlife Society has been tagging butterflies recently to learn more. Soon after the wintering generation leaves the Central Coast for homes as far away as Canada, they deposit eggs on milkweed plants and die. The second generation lives a few weeks then deposits eggs and dies, as does the third and sometimes fourth. Then the next generation eats heartily to get ready for the winter trip to the coast.

(Video: Monarch butterflies in Pacific Grove)

Eucalyptus Trees and Butterflies

Pacific Grove's monarch butterflies love to cluster in eucalyptus trees and Monterey pines (scientists call this "overwintering"). But why are those non-native eucalyptus trees there? Part of the answer can be found in the 19th century, when malaria was a scourge in California. Some doctors believed, incorrectly, that the disease was caused by "bad air" and felt the pungent oil of eucalyptus would clean the air. Thousands of the trees were planted here and around the state.
(Photo: Monarch Butterflies cling to eucalyptus trees in the sanctuary in Pacific Grove, CA. Courtesy of Inetours.)