Environment : Notes about your surroundings.

Fall color--Each fall, an estimated 100 million monarch butterflies living east of the Rockies make their way to a number of wintering sites in Mexico, clustering in spectacular displays made famous in TV nature specials and National Geographic photo essays.

In less staggering numbers, monarchs west of the Continental Divide head for the California coast. This fall, about 1 million of the large orange-and-black butterflies have gathered in sheltered groves of trees from northern Mendocino County to Ensenada, Mexico, according to Chris Nagano, an entomologist with the Los Angeles County Museum of Natural History. Numbers typically range from 1 million to 5 million, says Nagano, who is helping to coordinate a study of the monarch. In the last two years, Nagano and his associates have tagged 52,000 of the butterflies to learn more about their migration patterns and wintering habits--and to head off possible destruction of their wintering sites.

Although none of the nearly 100 West Coast wintering sites identified so far are in Orange County, Nagano says there have been reports of wintering monarchs in Seal Beach, Huntington Beach and San Juan Capistrano; he suspects there are also wintering sites in the coastal canyons near Laguna Beach. Anyone finding a dead tagged monarch is asked to send the complete specimen to Nagano. Written reports on possible wintering sites also are welcome. They can be sent to: Chris Nagano, Section of Entomology, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles 90007.