When Mia Monroe first began counting monarch butterflies in Marin County nearly three decades ago, she remembers seeing “tens of thousands of monarchs hanging—and when the sunshine hit them, it was like an orange cloud.” But in her time volunteering to count overwintering monarchs in West Marin, she has seen a precipitous decline in populations.
Each year during the three-week period around Thanksgiving, volunteers traverse coastal California to count the butterflies as part of the…