California IN BRIEF : TRUCKEE : Butterflies Flood the Sierra Nevada

Butterflies are streaming through the Sierra Nevada by the millions this month, turning the sky into a kaleidoscope of color and astounding insect watchers across the state. “This is the probably the best year for butterflies on record in Northern California,” said Arthur Shapiro, a professor of entomology at UC Davis. “It’s been good in the (Central) Valley too. But the mountains are where the action is.” Shapiro’s theory is that a hard freeze in December, 1990, knocked out some butterfly populations, but probably had a more devastating effect on their natural enemies--predators and parasites. Timely rains and mild winters have also contributed, he said.