By Paul Rogers / San Jose Mercury News
Monarch butterflies, the beloved orange-and-black insects that return each winter to the California coast, are in steep decline, according to a new study released Friday.
Monarch populations have fallen 74 percent in the past two decades, from roughly 1.2 million in 1997 to 292,674 in 2015 along the California coastline where they spend winters escaping the cold, according to the most extensive scientific survey done to date.
(D. ROSS CAMERON//Bay Area News Group archives)
“It’s pretty disturbing any time you have what was once one of the most common butterflies in the U.S. in decline like this,” said Emma Pelton, a biologist with the Xerces Society, a nonprofit group in Portland that published the study with funding from the U.S. Fish and Wildlife Service.
“Most children can identify one bug, and it’s monarch butterflies,” she said. “We’re seeing this decline in our lifetimes. It isn’t over 100 years, it’s over 18 years.”
The butterflies along the California coast are struggling because of development in and around the forested groves where they spend winters, pesticides such as glyphosate and other stresses, Pelton said.
Several environmental groups have petitioned the U.S. Fish and Wildlife Service to list monarchs as endangered, a decision the agency has said it will make by 2019.
The majestic, six-legged butterflies, which have wingspans of up to 5 inches, are generally grouped into two populations, eastern and western. The western population ranges west of the Rocky Mountains during warm months, breeding and feeding on milkweed and nectar from other plants, before heading every October to 412 known locations on the West Coast between Mendocino County and Baja California, Mexico.
Clumping together for warmth and shelter in eucalyptus, Monterey pine and other trees, the butterflies ride out the winter, heading back eastward by March. Multiple areas in California, including Santa Cruz, Pacific Grove and Pismo Beach, hold festivals and other events each year to celebrate the migration.
“We have thousands of people come every year,” said Abby Putnam, a park interpreter at Natural Bridges State Beach in Santa Cruz, where the annual Welcome Back Monarchs Day festival will be held Oct. 9 this year. “The butterflies are big, they are beautiful, they inspire a lot of people. They are graceful, they are gentle. And they don’t sting you like some other insects.”
Putnam said roughly 8,000 monarchs spent the winter this year in the towering eucalyptus groves of Natural Bridges. That’s up from 3,400 last year and 4,600 the year before, a jump she said might have been connected with the wetter conditions after four years of drought. But the total is still down from 120,000 in 1997….read more