Each fall, monarch butterflies from across the western United States flutter their way to the California coast to hole up for the winter. Mild temperatures, abundant nectar and protection offered by coastal forests have historically made California an ideal place for monarchs to survive into spring, and the majority of the population west of the Rocky Mountains make the annual trip to the state.
As recently as the 1980s, these iconic orange and black butterflies numbered in the millions. This season’s count, however, was much in line with the monarch’s decades-long severe decline. This year’s estimate, released last week, stands at about 29,000 monarchs, just above last year’s all-time low.
“This population has declined by over 99 percent,” said Emma Pelton, a conservation biologist with the Xerces Society for Invertebrate Conservation, which conducts the survey each year around Thanksgiving.
Pelton says the numbers indicate the historic western monarch migratory population is in danger of going extinct.