January 2, 2007 > Nature's Magicians
Their weight would barely tip a sensitive scale, yet these small beings magically change shape and perform amazing feats of geographical homing that would put professional pathfinders to shame. Known in scientific circles as Danaus plexippus, the Monarch Butterfly goes through a life cycle that is complex, fascinating and mysterious. These denizens of the sky begin their life journey as an egg usually deposited as the sole inhabitant of a milkweed plant leaf. The hatchling larva - a caterpillar - eats this singular diet voraciously until it curls into a pupa, also called a chrysalis, and undergoes an incredible transformation, emerging as a butterfly sipping flower nectar and finding a mate to begin the cycle all over again.
As remarkable as this pattern of life seems, these flying palettes of orange, black and white have another surprise talent. Their short life span of six to eight weeks does not allow a complete summer migration in a single generation. Instead, it may take three or four life cycles for the "grandchildren" or "great-grandchildren" to reach the limits of their summer habitat. As the days begin to grow shorter in August, these progeny, the so-called "long-lived" population with a life cycle of up to seven months and no first-hand knowledge of the northward journey, reverse course and travel at speeds up to 20 miles per hour and 100 miles per day sometimes at altitudes as high as 10,000 feet to wintering locales in a single generation! How can a great grandchild radically change its life cycle and inherit the knowledge of four previous generations to find the ancestral originating place? It is a baffling mystery of the Monarch Butterfly.
Fortunately, Ardenwood is known to about 1600 of these creatures as they return en mass in early winter months to Eucalyptus groves huddling together for warmth during the cold of December, January and February. Other Eucalyptus groves along the coast and bay waters offer sanctuary for these magical creatures too until, as the days begin to lengthen and the sun warms the air, swarms of Monarchs fill the air and find a mate to begin the northward journey again.
At Ardenwood Historic Farm, naturalists are ready each year to help others learn about the mysteries of Monarchs and view them as they prepare for spring and summer. Ardenwood Naturalist Chris Garcia says that there are two major groups of Monarchs divided by the Rocky Mountains. The group that inhabits Ardenwood is obviously part of the western group. Each year, this phenomenon is the subject of many "Monarch Butterfly Walks" at the park. She notes that they are split into three basic groups: Monarchs for Kids designed to help youngsters understand the life cycle through puppets and role-playing; Meet the Monarchs for those who would like to understand the biology and science of these insects as well as view them; and Monarch Butterfly Walks that include a short narrative, but focus primarily on viewing.
There are definite stages to wintering patterns. For much of the colder months, the Monarchs huddle together in clusters and form insulating "shingles" with their bodies. Occasional movement can be seen as individuals vie for warmer places but the group stays firmly planted on branches using "barbed" feet. Activity and mating is reserved for warmer days when the chance of survival of offspring is great. As the days grow longer in February, activity quickens and by mid-month, the Monarchs begin the spring and summer, multi-generation journey north and east. Not all Monarchs migrate, but Garcia notes that food sources and the local ecology can only support a relative few that may remain in the area during the summer. For most, the hunt for a special milkweed leaf that will nourish their offspring drives them out of the area.
Although the Monarchs congregate in some other local areas, Ardenwood offers a great opportunity to visit them with the expert guidance of naturalist guides. While you are visiting, ask about the opportunities to become a docent at the park. There are a wide variety of positions available including animal care, participation as a historical figure or demonstrating traditional crafts such as cooking on a wood stove, farming, wool spinning and much more. And fun is guaranteed! If you are interested in being a docent, call Chris Garcia at Ardenwood (510) 796-0663. A training session will begin Saturday, February 24 and continue for five Saturdays from 9:30 a.m. - 12:30 p.m.
Ardenwood Historic Farm
34600 Ardenwood Blvd., Fremont