Two such sites exist in eucalyptus forests within the East Bay Regional Park District: one at Pt. Pinole Regional Shoreline and the other at Ardenwood Historic Farm. Tours of these sites are made available through the naturalist staff by reser- vation only.

Monarch egg on underside of milkweed leaf. Monarch Development Monarch chrysalis Monarch eggs develop and hatch in about four days. Tiny emerging caterpillars dine Within the chrysalis, the body of the caterpil- Monarch caterpillars from newly hatched to voraciously on milkweed leaves and increase lar dissolves into what has been called a “liv- full grown. in size 2,700 to 3,000 times in the first two ing soup” and its cells rearrange to form the weeks of life. If a human baby developed this exquisite adult butterfly. This metamorphosis An Intriguing Insect rapidly it would be the size of a blue whale by takes 10 to 15 days. The Monarch Butterfly The monarch butterfly weighs only 1/50 two weeks of age. Growing to two full inches Enclosed within a quiet eucalyptus grove of an ounce. Yet, it can travel up to 20 in length, the plump black, yellow, and white and clustered more thickly than leaves are m.p.h. and has been sighted by glider pilots striped caterpillar completes its development thousands of monarch butterflies. Gradually, at elevations of 10,000 feet. It migrates and prepares for transformation into the adult as dappled sunlight warms the grove, they hundreds to thousands of miles each year form. begin opening their wings to bask. Entire to reach ancestral overwintering sites it has branches, layered with butterflies, turn vivid never visited before. The behavior of this orange and black. Suddenly a cascade occurs. remarkable butterfly is considered unique The warming air has increased the temperature – no other insect known to science has as within a cluster and hundreds of monarchs long and precise a migration pattern. become active in the same instant. Releasing their hold on the branches, they flutter sky- Native to North America, monarchs are ward filling the air above your head. They are divided into two populations: one east and so close and so numerous you can hear the one west of the Rocky Mountains. At the peaceful “susurrus,” the whispering sound like end of the breeding season each August, Monarch butterfly emerging from a distant waterfall, made by the movement of most of the monarchs living west of the the chrysalis. their wings. Rockies migrate toward coastal California to overwinter in one of the approximately Monarchs emerging from the chrysalis in The scene described above may sound like a 100 known monarch sites. Eastern monarchs spring live only about two more weeks, long dream or the product of wild imaginings. Yet, migrate to overwintering sites in Mexico. Monarch caterpillar attached upside down enough to travel farther north and east in it is a common natural occurrence each year preparing to shed its skin. search of milkweed, reproduce, and die. Like from November through February at monarch After wintering, monarchs search for patches the first spring monarchs, succeeding spring overwintering sites along California’s coast. of milkweed, moving north and east from Searching out a sheltered location, the cat- and summer generations live only six weeks. the California coast. When this host plant erpillar attaches itself to a solid object and Thus, generations of monarch butterflies To witness this natural spectacle is an experi- is located, the female carefully lays 100 or hangs upside down. Here it sheds its old skin continue the north and eastward migration ence not to be missed and never to be more eggs and then both males and females and hardens its new skin into a jewel-like case as spring arrives and milkweed grows in the forgotten. of the overwintering generation die. called the chrysalis. northern latitudes. The Migrants Return Protecting Monarchs Visitor Centers By late August as the fifth generation of mon- Because all living monarchs cluster in rela- ARDENWOOD HISTORIC FARM Monarchs archs develop, the days begin to grow shorter tively few sites each winter, destruction of Fremont (510) 796-0663 and nights become cooler. These butterflies, even one site impacts a large percentage of the [email protected] sensing the coming change of season, quickly population. With the increase of development increase body fat and delay mating. They in California, biologists consider monarch BLACK DIAMOND MINES begin their long migration south and west overwintering to be an “endangered phenom- Antioch (925) 757-2620 into California to find the ancestral overwin- enon.” As open space disappears, acres of [email protected] tering site they have never seen before. Here, wildflowers which supply nectar for migrating they gather to wait out the winter. Those that monarchs and dozens of other butterfly spe- COYOTE HILLS REGIONAL PARK survive will reproduce the following spring, cies are lost. Without protection, the West- Fremont (510) 795-9385 having lived to the ripe old age of six months, ern monarch and many of its relatives could [email protected] or more. become endangered species in the near future. CRAB COVE at CROWN BEACH Biologists today are just beginning to fully Alameda (510) 521-6887 understand the complex relay race of monarch [email protected] migration. How do monarchs know precisely What You Can Do where to find their overwintering sites when You can help the monarch by safeguard- SUNOL REGIONAL WILDERNESS no individual butterfly has ever made the ing overwintering sites, as the Regional Park Sunol (925) 862-2601 round trip? If a monarch from Ardenwood District has done at Ardenwood Historic Farm [email protected] mates with a monarch from Monterey, where and Pt. Pinole Regional Shoreline. You can also will their offspring overwinter? Many myster- turn your own yard, patio, and/or garden into TILDEN NATURE AREA/EEC ies are yet to be solved. But, we do know that “butterfly-friendly” habitat. One way to do this and LITTLE FARM protecting overwintering sites is essential to is by planting specific nectar-producing flowers Berkeley (510) 525-2233 the survival of the species. and milkweed plants and by restricting your [email protected] use of pesticides. Further Reading: For more information on establishing a butterfly garden, see the EBRPD brochure Common Butterflies of California, Stewart Butterfly Gardening available at the District’s California Butterflies, Garth & Tilden visitor centers. In addition, you may wish to Western Butterflies, Opler call Coyote Hills Regional Park to arrange a visit to the butterfly garden. (510) 795-9385 This brochure is provided as a public service of the Interpretive and Recreation Services The Regional Parks Botanic Garden, located Department of the East Bay Regional Park in Tilden Park, Berkeley, has an annual na- District. For more information, call one tive plant sale on the third Saturday of April. of the visitor centers listed above. Many butterfly-attracting plants are available. (510) 841-8732 East Bay Regional Park District 2950 Peralta Oaks Ct., P.O. Box 5381 Text by Jan Southworth Oakland, CA 94605-0381 Photos by Rachel Lamoreux, Jan Southworth, (510) 635-0135 and Karen Oberhauser TDD phone (510) 633-0460 www.ebparks.org East Bay Regional Park District 11/06 www.ebparks.org