Butterfly Migration Is Early, Large; Weather System Credited

El Nino is apparently bringing more than just weird weather and talkative meteorologists to Southern California.

The much-hyped meteorological condition also seems to have coaxed the largest and earliest migration of monarch butterflies to their California winter nesting grounds ever.

Tens of thousands of monarch butterflies are flitting about more than 300 nesting sites in Ventura County and elsewhere in the state weeks earlier than normal.

“I’ve been working with monarchs for 10 years now and I’ve never seen anything like it,” said David Marriott, executive director of the nonprofit Monarch Program in Encinitas, Calif. “There are tens of thousands of butterflies that have already reached the San Francisco Bay Area by the first week of October and that’s very unusual. . . . It’s possible the weather conditions of El Nino are affecting the monarch populations this year.”

The distinctive orange-and-black butterflies have begun to arrive in coastal parks near the Ventura-Los Angeles county lines as well, a phenomenon that doesn’t usually occur until the beginning of November, said Christina Craig, a ranger at Point Mugu State Park and Leo Carrillo State Beach.

“We are seeing great numbers of them, especially in Sycamore Canyon Campground and the eucalyptus trees by Leo Carrillo State Beach,” she said. “We generally don’t see them in these numbers.”

About 800 monarch butterflies are expected at Leo Carrillo this winter, Marriott said.

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But that figure is dwarfed by the estimated 10,000 butterflies that are expected to hang in huge clusters from the branches of a grove of eucalyptus trees in a barranca in Ventura’s Camino Real Park around Thanksgiving when the monarch population peaks, Marriott said.

On Friday, stately monarchs could already be seen flitting through the quiet sunlit dell with only the tapping of a nearby woodpecker breaking the silence.

“We’ve seen quite a few,” said Kathryn Babcock, whose backyard on Dean Drive overlooks the barranca. “Usually it’s November, later in the year. . . . They are one of the delights of living here because they swarm and at night you can see them hanging from the trees like grapes.”

The migration of the fragile monarchs, which can journey hundreds of miles along the West Coast, is considered one of nature’s great annual spectacles.

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It is all the more amazing because unlike other migratory creatures, the tiny monarchs live only a matter of months. Therefore those heading south today have never seen the winter roosts they’re headed for.

At two sites in California, Pismo Beach and Santa Cruz, an incredible 100,000 monarchs gather annually. But there are nesting sites in every county from Sonoma County south.

Weather conditions linked to El Nino in both Northern and Southern California have conspired to produce the same effect: more butterflies, Marriott said.

Northern California’s monarchs come from the Pacific Northwest, which has seen an unusually wet and cool summer that scientists say stems in part from El Nino.

Coastal sections of Washington and Oregon have seen rainfall more than 11 inches above average and temperatures 3 to 5 degrees below normal this summer and fall, said meteorologist Wes Etheridge with WeatherData Inc., a private company that provides weather forecasts for The Times.

That’s led to more and larger milkweed plants--the monarch’s only source of sustenance--there and a subsequent monarch population explosion. In addition, the cooler temperatures are prompting the butterflies to fly south early.

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In Southern California, a wet winter followed by a hot summer--and the bountiful crop of milkweed--has produced hundreds of monarchs in the foothills of the Sierras, and also in Arizona, Utah and western Colorado.

Moreover, early winter snows in the Sierras coupled with this year’s especially persistent Santa Anas are enabling those monarchs to arrive here sooner than usual.

“We don’t know if it’s a coincidence that the high population is occurring this year . . . or [if] the weather conditions of El Nino are affecting high populations,” he said. “In previous El Nino years, monarch populations have been high.”

Still, those who welcome the colorful winter visitors each year are pleased that the weather system, threatening torrential rains, may have brought something positive to the region. The monarch population had diminished in recent years.

“I’m delighted to have monarchs again,” said retiree Barbara Born, who also lives near Camino Real Park. “Years ago . . . the sky would be full of them.”

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FYI

The Monarch Program, which has an annual open house scheduled for the next two weekends at its Encinitas headquarters, recently produced a brochure listing the state’s top sites. Call (800) 606-6627 for information.