Where have all the monarchs gone?

PISMO BEACH, Calif. (CN) — In a small tree grove at the south end of Pismo Beach on California's Central Coast, one visitor has arrived with a long telephoto lens while others take photos with their smartphones or simply stare up at the trees.

Several monarch butterflies flutter around the grove or land on a tree branch for a pit stop, but this year has offered significantly fewer monarch photo opportunities. According to numbers posted on a nearby whiteboard, the population peaked at 556 this season.

“When I was a little girl, there were 250,000 at the Pismo State Beach Monarch Butterfly Grove, and I’m 39,” said Danielle Bronson, a state park interpreter for the Oceano Dunes District.

Knowing climate change and pesticides can harm the monarchs, their food sources and habitat, the federal government has proposed listing the insect as threatened under the Endangers Species Act, which would provide protections and strategies to help resurrect the population. Currently in the public comment phase until March 12, protections offer hope to a species that has declined over 95% since the 1980s, Bronson said.

“Insects are really resilient if the conditions are right,” she said. “If the conditions are right, they can bounce back.”

Known for its bright orange and black colors with white spots, the monarchs are the most popular butterfly in North America, often seen in gardens, prairies and natural areas, according to the Xerces Society for Invertebrate Conservation, which conducts annual monarch counts and advocates for protections. Every year, the Western monarchs migrate to the warmer California climate during the winter, typically between November and February.

At the peak, in 1997, 1.2 million monarchs migrated to California. This year, only 9,119 were counted across the state.

At the small grove in Pismo Beach, tourists have long flocked to the site during the winter holidays to witness thick clusters of butterflies perched on eucalyptus, willow, Monterey cypress and pine trees as dozens flutter about in a feel-good nature scene that channels a Disney movie.

“It’s a tradition for families,” Bronson said. “They want to share an outdoor experience together.”

While that ecotourism is important to a place like Pismo Beach, also known for its Pismo clam, the butterflies are also important to the ecosystem. They pollinate native nectars, and when they are in the caterpillar stage, they provide an important source of food for birds and animals.

“We estimate, conservatively, that only 5% of them make it to adulthood,” said Emma Pelton, senior endangered species conservation biologist for Xerces. “So that means a lot of the caterpillars are eaten.”

Luckily for the monarchs, females lay up to 300 eggs at a time, increasing the likelihood of species growth.

“There’s hope in the fact that they just reproduce so much,” Pelton said.

After numbers in Pismo dipped to a staggering low of 199 in 2020, the next year, the population was over 20,000.

“They do have an incredible capacity to rebound quickly,” Pelton said, “which also means they have an incredible capacity to crash quickly, so it’s like a blessing and a curse.”

Predators have always posed a threat to the butterflies. But more recent phenomenon have worsened their odds. Climate change produces severe weather, such as California’s hot 2024 summer.

“This past year was incredibly hot in July,” Pelton said. “It was the hottest month ever on record in California.”

Combined with a drought, those hot temperatures threaten trees monarchs live on and the milkweed they rely on for food, she said. Meanwhile, pesticides — not just from farms but also household sprays for insects, weeds and rodents — can cause harm. In January, 2024, hundreds of monarchs at the Pacific Grove Monarch Sanctuary in Monterey County  were found dead or convulsing from pesticides, Pelton said.

If the butterflies are determined to be a threatened species, the government can be proactive in protecting them. Pismo Beach, where the grove is located on state land, serves as an example of what can be done.

“We have developed a management plan for our overwintering site,” Bronson said.

There, trails have been established for visitors, along with fencing that keeps visitors from the trees where the butterflies perch. Butterflies don’t typically fly when the temperature is below 54 degrees, and they will often fall to the ground, where they could be stomped to death, Bronson said.

Since cormorants pose a threat to some of the trees in the grove, the state has pursued nonlethal measures to keep the aquatic birds away. And because yellowjacket bees attack the monarchs — not to mention visitors — they’ve reduced bee populations.

Despite the population decline at the Pismo State Beach Monarch Butterfly Grove, it has fared better than others in the state, showing that proactive measures work.

“They’ve planted trees,” said Pelton, whose organization partners with the state. “They’ve put in a lot of native nectar plants.”

No one is sure how long the butterflies have been coming to Pismo Beach. Eucalyptus trees from Australia — which butterflies enjoy — were planted there 120 years ago as a windbreak for a nearby artichoke field, Bronson said. Since packed groves also appeal to butterflies, which seek shelter from wind and rain, they likely have migrated to Pismo Beach for decades. But the monarchs weren’t officially discovered there until the 1960s, when rangers responding to a brushfire discovered thousands of butterflies.

Through the years, the butterflies prospered at the grove, located next to a campground and near a residential neighborhood, providing picture-perfect opportunities for amateur and pro shutterbugs.

On a recent February weekend, the whiteboard at the grove listed the current count at 40, reflecting not only this year’s lower overall numbers but also the end of the monarch season. By this time, many monarchs — which can travel up to 200 miles a day — have already headed back to states like Oregon, Washington, Idaho and Utah.

But the lower numbers didn’t deter a steady stream of visitors.

“When the general public comes, it’s still a site to behold because you don’t see 40 butterflies in your backyard,” Bronson said. “So it gets them excited, but you don’t get that true ‘wow’ effect of those clusters.”