Why we're seeing wave after wave of butterflies in Ventura County

Ventura

After a spring surge that eclipsed recent years, Ventura County is seeing wave after wave of monarch-like painted lady butterflies.

It’s all part of their migration north.

There was a huge bloom of butterflies in March, thanks to a wet winter, and you might have thought you’d see them no more once they passed through. But they’ve kept popping up in waves.

According to Ventura-based entomologist Anna Howell, the painted ladies we’re seeing now are hatched from the eggs laid by the ones that first came through in March

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They’re prospering, thanks to the amount of vegetation made possible by the wet winter. With greater food sources for the caterpillars, we’re seeing more butterflies than usual, even months after the initial migration.

“It’s a very high number, especially since we’ve been in a drought,” Howell said.

The last time Ventura County saw this many butterflies was back in 2005, which also had a heavy rain season. There were even more butterflies that year, according to Howell.

Jim Cornett, lead ecologist for Palm Springs-based JWC Ecological Consultants, said the initial appearances of painted lady butterflies are in northern Mexico. Some of them stay behind in Mexico to keep the population intact, but others start moving north.

Each successive generation of the butterflies will lay eggs until they die off farther north. They fly in that direction, he said, because their genes tell them to move away from the sun and fly toward darker skies.

Howell said we can expect to see migrating butterflies in the area until about June, when they reach their destination in Northern California and the Pacific Northwest.

“If there’s enough resources, they’ll go higher. Otherwise, they’ll stick around Northern California,” Howell said.

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The butterflies will begin traveling back south through the region in August before ending up near the border with Mexico.

They may look a lot like monarchs, but they’re not in trouble like that species.

“They’re not monarchs. People have been reading in the media they’re nearing extinction in California,” said Arthur Shapiro, evolution and ecology professor at UC Davis. “Painted ladies have a much higher reproductive potential in California.”

The non-endangered painted lady is a resilient species that lives on most continents, according to Matthew Shepherd, director of communications and outreach for the Xerces Society, a nonprofit that focuses on conservation of invertebrates and their habitats.

Although painted ladies can be seen throughout Ventura County, you’ll probably find more in warmer areas with higher elevations, like the Ojai and Conejo valleys.

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“Warm weather speeds up their developmental time and pushes them into their adult stage,” Howell said. “From egg to final adult stage takes about two months.”

She recommended looking out for the butterflies as long as possible, because they won’t be around forever.

“Just enjoy them while they’re here,” Howell said.

Contributing: Eduardo Cuevas and Shane Newell, USA TODAY Network — California

Jeremy Childs is a breaking news and public safety reporter covering the night shift for the Ventura County Star. He can be reached by calling 805-437-0208 or emailing jeremy.childs@vcstar.com.