Where Are CA's Monarch Butterflies? With The Population In Free Fall, A Call To Arms Is Issued

Last winter, California saw a 95 percent drop in western monarch butterflies wintering in the Golden State's famed butterfly groves, and this week the California State Parks Foundation is asking residents to take steps to help with the survival of the species.

The California State Parks Foundation is asking the public to observe and report sightings of western monarch butterflies during California Biodiversity Week from September 6 to 14. The data from these observations will help scientists understand where these butterflies are at different times of the year and will also help inform the upcoming 29th annual Western Monarch Count.

Habitat loss, extreme weather from climate change and pesticide use are threatening the species' survival. According to CalMatters, volunteers from the Xerces Society, tallied less than 10,000 monarchs last winter down from more than 200,000 in previous years.

Right about now, California residents are seeing the Western Monarch butterflies that will soon make their way to coastal butterfly groves to overwinter.

In late August of 2025, numerous Western Monarch butterflies were spotted in Orange, San Diego and Riverside counties. By early September, Patch editors had tracked them further north and west, in Orange County's Garden Grove and Seal Beach. They are headed to their overwinter grounds, many in Central California.

Randy Widera, Director of Programs for California State Parks Foundation, spoke on the annual Western Monarch Count in California.

"Millions of western monarchs used to return to coastal California every year, but the population has plummeted in recent decades. Numerous factors have contributed to this decline, including climate change, habitat loss, pesticides, and disease," according to Widera.

Last year's 28th annual Western Monarch Count found a peak population of 9,119 monarchs, the second-lowest overwintering population ever recorded since tracking began in 1997. A Species Status Assessment predicts a greater than 95% chance of extinction for western monarchs by 2080.

“The western monarch butterfly is an iconic species for our state,” Widera said in a recent news release. “Californians have a key role to play in the preservation of this species, from helping scientists track where the butterflies are located to advocating for the protection of their habitat. We’re encouraging Californians to get involved by taking a few easy steps to report monarch butterfly sightings.”

As California Biodiversity Week is celebrated, Californians who want to participate in the process of observing and reporting monarch butterfly sightings can do so with the following steps:

• Download the free iNaturalist app and start an account on either the Apple App Store or Google Play.
• Snap a photo of a monarch butterfly or monarch caterpillar.
• Upload an observation to iNaturalist.

California’s state parks provide critical habitat for western monarch butterflies.

Last year, the California State Parks Foundation released an analysis of 26 years of data on the western monarch butterfly population, showing that a significant number of those counted are found in California state parks.

Central California state parks are an essential area where those butterflies will spend the winter, experts say. Between 2024 and 2025, Lighthouse Field State Beach, Natural Bridges State Beach, and Pismo State Beach were noted as the top western monarch overwintering sites.

"Overwintering is a vital phase in a western monarch butterfly's life cycle, offering rest and energy conservation before spring mating and northward migration. Overwintering groves provide the specific microclimate the western monarchs need to survive, including protection from the wind and cold, dappled sunlight, and ample nectar sources," Widera said.

Monarchs spend the winter in groves in Natural Bridges State Beach, Lighthouse Field State Beach, New Brighton State Beach, Point Lobos State Natural Reserve, Andrew Molera State Park, Morro Bay State Park, Montaña de Oro State Park, Pismo State Beach, Gaviota State Park, Point Mugu State Park, Leo Carrillo State Park, Doheny State Beach, San Clemente State Park, and Torrey Pines State Natural Reserve.

California State Parks Foundation has helped lead the development of "overwintering grove management" plans at several state parks. The organization has also funded restoration projects and helped organize volunteer events where participants support the monarch butterfly population through activities such as planting native nectar plants. It is also advocating for western monarch butterflies to be listed as a threatened species under the U.S. Endangered Species Act.

"Western monarch butterflies are considered an iconic species because of their beloved status among the public and for their critical role in the food web" Emma Pelton, a biologist at the Xerces Society told CalMatters. Besides being pollinators, they’re food for birds, insects and some mammals.

"Their migration also attracts visitors to California state beaches, particularly in Santa Cruz and Oceano. Moreno estimates that over 80,000 people visit sites, including Pismo State Beach’s monarch grove, per year.

California lawmakers have passed laws to protect the species: A decade ago, the state directed the California Department of Fish and Wildlife to conserve the butterflies and their habitats; and in 2018 the state established the Monarch and Pollinator Rescue Program."

Californians interested in supporting this effort can sign a petition at www.calparks.org/monarchthreat.