Stormy Season Batters Butterflies

This winter many sites in the state's Central Valley were flooded, putting the butterflies' emergence several weeks behind schedule. For instance, on one day recently when Shapiro normally would have seen about 100 individual butterflies from 10 different species, he saw only three butterflies, all cabbage-butterfly species.

Word is still not in on El Niño's effects on monarch butterflies, which spend winters in coastal groves and breed inland. In the Central Valley, the milkweed plants that monarchs feed on were late in sprouting. If the 1997-98 winter and spring season concludes like 1982-83 did, the most dramatic deviations from normal will be seen in the high-Sierra butterflies. Very late snow melt will delay their emergence and shorten their breeding season, according to Shapiro. At the highest altitudes, some species may even skip a full year.