Because they can't tolerate extremely cold temperatures, when winter approaches, Western monarch butterflies fly from the western Rockies to the California coastline and take refuge at Pismo State Beach Monarch Butterfly Grove on Highway 1.
There have been some rare instances when park staffers found butterflies that have come from British Columbia, Oregon and Arizona throughout the season, according to Cheryl Powers, docent at the grove.
Those butterflies were tagged by researchers from those areas, and once they arrive here, staff members contact the researchers and let them know that "their friends" made it safely to the California coast, she said.
"The monarch butterflies are here to enjoy this beautiful weather, just like the rest of us, because they can't tolerate freezing conditions," Powers said. "Monarchs can't fly unless it's above 55 degrees, and can't tolerate overnight freezing temperatures for more than a couple of days."
In the 1990s, there were as many as 200,000 monarch butterflies at the grove during the winter season. However, in 2016, the population dropped to 20,000, the smallest in two decades.
This year, 14,000 monarch butterflies were counted Thanksgiving Day. On Saturday morning, Powers and her staff counted 12,000.
"We lost about 90 percent of the monarch population in the last 20 years, so there's been a dramatic decline," said David Curtius, docent with the San Luis Obispo Coast Area State Parks. "We lost a lot of milkweed habitats, because there's been so much agricultural and urban development that's plowed through so much of it."
Monarch butterflies can't survive without milkweed, and need it to lay their eggs, Curtius added. The decrease in rainfall also affects milkweed population.
Despite the monarch butterfly population in Pismo being at an all-time low, that didn't stop a crowd of visitors from arriving to peek at the clusters up in the eucalyptus trees.
Jamie Chambers, 38, a wildlife technician, drove from Tehachapi in the Mojave Desert area. She and a few friends from San Francisco had traveled to Morro Bay to enjoy some sightseeing for the New Year's weekend.
"It's my first time here today, and I was really relieved when I found this grove on Google, because the only other place I knew of that had a similar site to this was in Big Sur," Chambers said. "I wanted to make it out here today because it feels like a once-in-a-lifetime event.
"Just like the butterflies, if I were to move away, I'd have to travel extensively to get here. How often could I tell people I saw thousands of butterflies gathered together?"
Chambers noted that many of the fellow tourists and visitors she met Saturday morning "came from Europe, Asia, Canada and all over the place."
"It's kind of like the same way monarchs travel everywhere to unite together in one place," she added. "It's cool if you think about it — and cheesy at the same time. They're all converging here at this very spot to get away from the cold, and we're all converging here, too."
As Chambers photographed a close-up of a cluster of butterflies with their wings folded down, resembling a bunch of leaves hanging off a branch, she noted that one of her resolutions for the new year is to travel more.
"I just want to see stuff like this grove a lot more in the future," she said. "Just try to spread love and light out in the world now more than ever, too; we definitely need it. I think about it a lot when I'm out near wildlife, like I'm here today."