Have the monarchs from Central Mexico reached California already? Read on!
To: Journey North From: The First Grade Classes at Montecito Union School Santa Barbara, California E-Mail: cbalch@aol.com
"Greetings from Santa Barbara, California! The 3 First Grade Classes from Montectio Union School went to Ellwood Grove in Goleta to observe the monarch butterflies. Here is what the first graders had to say about their trip:
On February 22, 1995 at 10:00 a.m. we arrived at the grove. We saw lots of butterflies. There were some boys who counted more than 100 butterflies. We saw 6 butterflies mating. The butterflies, when they were mating, they flew and the male carried the female. We saw butterflies on the ground. We almost stepped on two butterflies mating. We moved them over next to a tree. We found a butterfly with a tag on it and have sent it to the address that was on the tag. We were looking for milkweed. We didn't find any. The grove is filled with eucalyptus trees. We didn't find as many butterflies as we thought we would. In years past, there have been thousands of butterflies. We think that there weren't as many this year because it has been hot and they started to fly away.
We hope you enjoyed our report and find monarchs were you live."
Before you mark Goleta, California on your migration map here's some important information that you should know:
There are 2 major populations of monarchs in North America, one that winters in central Mexico and another that winters along the Pacific coast. (A "population" is a geographically distinct group of animals or plants of the same species that are separated by a physical boundary.) The monarch colonies in California are quite different from those in central Mexico. In contrast to the great concentrations of butterflies at 9 sites in Mexico, the western monarch population winters along a 600 mile stretch of the Pacific coast. There are more than 150 colonies extending from Ensenada, Baja California, Mexico to Sea Ranch, California (just north of San Francisco in Sonoma County). See if you can find these locations on a map. Then locate the three largest monarch wintering sites, listed below, on the same map.
CHALLENGE QUESTIONS:
See if you can answer the following questions with the help of a physical map of North America.
1) Why do you think there are two populations of monarch butterflies in North America?
2) Where do you think monarchs from the following places would spend the winter?
a) Denver, Colorado b) Portland, Oregon c) Boise, Idaho
3) Why do you think there are over 150 monarch wintering sites in California but only 9 in Mexico?
Send your answers to: jnorth@informns.k12.mn.us
Even in a good year, almost all of the 150 West Coast colonies are relatively small, with under 20,000 monarchs at each site. Only 3 sites have a population of over 100,000 butterflies. For the past few years, however, people have become very concerned about the west coast monarchs. The population has fallen drastically since 1991. This year there are 90-100% fewer at each site! The chart below compares the normal population size to the size this year at the 3 largest sanctuaries:
Normal Size Size This Year
Pismo Beach, CA 180,000 15,000 Pismo State Beach
Goleta, CA 100,000 5,000 Ellwood Sites
Davenport, CA 170,000 4,000 Natural Bridges State Beach
David Marriott, editor of "The Monarch Newsletter", reports:
"People want to know, 'What's happening to the monarch?' Our response is usually a combination of : 1) a natural fluctuation in insect populations, 2) drought, 3) climate conditions and 4) viruses or parasites...Nobody really knows what's happening! "
Based on observations this winter in California, Marriott now believes that a protozoan disease is contributing to the decline. He's organizing a research effort in order to study the problem more closely this summer.
If you would like to help raise money to support this effort, or if you'd like to subscribe to his monthly monarch newsletter, contact:
The Monarch Program, P.O. Box 178671, San Diego, California 92117
Copyright 1995, Journey North. All Rights Reserved.