In honor of California Biodiversity Day, the County of Marin’s Board of Supervisors recognized the need for our communities to support the western monarch butterfly population with conservation efforts.

The Resolution was introduced by District 4 Supervisor, Dennis Rodoni, whose district supports historic overwintering grounds for the butterfly in the coastal villages of Bolinas and Stinson Beach. The fall and winter monarch coastal overwintering phenomenon has been in steep decline since the 1980s as the populations are under stressors from habitat loss, pesticide use, invasive plants, and more.

Fall has arrived and with anticipation we are waiting for the arrival of the western monarch butterfly to their overwintering grounds along the Pacific Coast, typically beginning in September and lasting through February. Unfortunately, the butterflies are in crisis. In the 1980s, it is estimated that there were 4.5 million butterflies counted at overwintering locations along the Pacific Coast. Last year, volunteers counted only 2,000 butterflies along the Pacific Coast. This is a drop of more than 99 percent in the population.

There are many factors contributing to the dramatic decline in monarch butterflies including habitat loss, use of pesticides and toxic chemicals, disease and parasites, and changing conditions related to the climate crisis.

Additionally, well-intentioned individuals can harm monarch butterflies by planting non-native milkweed, like tropical milkweed, that continues to bloom all year and confuses monarchs’ reproductive cycle. Monarchs and milkweed have an important relationship, however, one cannot rely only on planting milkweed to save monarchs. Depending on where you live, milkweed may not be the answer.

Earlier this year, EAC released our report on the western monarch butterfly, Marin’s Monarch Movement, and wanted to share some of the progress being made throughout the County.

Our report helped to inspire a working group who meets monthly to share and coordinate efforts to protect and support the population of western monarch butterflies. This forum is an important gathering place to share information and coordinate on projects.

…In an effort to expand public education, we are happy to release two of EAC’s previously recorded webinars focused on the monarch butterfly that were filmed in March and April 2021. The UC Master Gardeners have created an information video about the western monarch butterfly and what you can do to help the butterfly populations in your backyard.