USA TODAY US Edition
San Francisco: The western monarch butterfly population wintering along the state’s coast remains critically low for the second year in a row, according to an environmental group. The Xerces Society recorded about 29,000 butterflies in its annual survey. By comparison, about 4.5 million monarch butterflies wintered in forested groves along the California coast in the 1980s. Scientists say the butterflies are at critically low levels in the western U.S. due to the destruction of milkweed along their migratory route as housing expands and use of pesticides and herbicides increases. Researchers also note the effect of climate change.