But the count this year is dismal. At iconic monarch wintering sites in the city of Pacific Grove, volunteers didn’t see a single butterfly this winter. Other well-known locations, such as Pismo State Beach Monarch Butterfly Grove and Natural Bridges State Park, only hosted a few hundred butterflies, researchers said.
“These sites normally host thousands of butterflies, and their absence this year was heartbreaking for volunteers and visitors flocking to these locales hoping to catch a glimpse of the awe-inspiring clusters of monarch butterflies,” said Sarina Jepsen, director of endangered species at the Xerces Society.
Scientists say the butterflies are at critically low levels in western states because of destruction to their milkweed habitat along their migratory route as housing expands into their territory and use of pesticides and herbicides increases.
Researchers also have noted the effect of climate change. Along with farming, climate change is one of the main drivers of the monarch’s threatened extinction, disrupting an annual 3,000-mile (4,828-kilometer) migration synched to springtime and the blossoming of wildflowers. Massive wildfires throughout the U.S. West last year may have influenced their breeding and migration, researchers said.
A 2017 study by Washington State University researchers predicted that if the monarch population dropped below 30,000, the species would likely go extinct in the next few decades if nothing is done to save them.