First time observed: Hundreds of monarch butterflies cluster in Berkeley’s Aquatic Park

In late October, Berkeleyside received a tip that thousands of tiny fish were jumping in the waters of Aquatic Park.

Less than three weeks later, we received another “scoop” about the park that throngs of monarch butterflies were clustering in the trees.

I’d seen groups of monarchs in well-known gathering places, called “roosts” or “bivouacs,” in Pacific Grove and Santa Cruz. But I’d never heard of such a spectacle in Berkeley.

So I rushed the next morning to Aquatic Park, to the trees just east of the 14th hole of the disc-golf course, the site where the butterflies had purportedly been spotted.

I arrived before 9 a.m., when the air remained cool and clear. And, as expected, the monarchs were hunkered down, huddled together, wings closed.

I hunkered down, too, waiting for the sun to rise higher in the sky and warm the pendant-like clusters. That’s when the fluttering would begin.

“2015 has been the biggest monarch year in northern and central California in at least a decade,” says Distinguished Professor Arthur M. Shapiro from the Department of Evolution and Ecology, College of Biological Sciences at UC Davis.

“And,” he adds, “the pattern of breeding returned to the historic one seen in the 1970s-80s.”

California monarchs suffered declining numbers for ten years or more; they began to rebound in 2014.

“The cause or causes [of the past decline in monarch populations] remain unknown,” says Professor Shapiro. “But they are not related to the amount of milkweed; we were seeing lots of milkweed not being used because the butterflies weren’t there to use it!”

Milkweed is the monarch’s “host plant,” the only plant it eats as a caterpillar and the plant upon which females lay their eggs. Some people grow milkweed in their gardens in the hopes of attracting monarchs.

As for the large groupings of monarchs in Berkeley, Mia Monroe, volunteer with The Xerces Society, and coordinator of the Western Monarch Thanksgiving Count, says that the news is “very exciting.”

“This is the first year monarchs have been observed resting and clustering in Berkeley’s Aquatic Park,” she says.

Monroe calls the new Berkeley butterfly roost one of the “unexpected surprises” in this high-abundance year, and she says that citizen scientists are adding the site to the list of places they will monitor.

Only time will tell how long the monarchs will stay in the park — whether they will use the trees as a temporary yet critical rest stop before moving on to another refuge, or whether they will find lasting protection there through the winter’s storms.

Each year, monarchs gather in more than 200 overwintering sites in California, usually close to the coast. They come from areas west of the Rockies and as far north as Washington State. Most will leave in spring, flitting back toward the north and east.

By 1 p.m., it was time for me to make like a springtime monarch, and go. I’d spent more than four hours with the butterflies, watching, photographing, wondering. I’d met friendly dog walkers, listened to passing trains and young children counting butterflies, declined the offer of a hit from a blown-glass pipe.

I took one last look above me…

… then I pulled myself away.

As I walked the path back to my car, I encountered two more friendly people, outfitted with hiking gear and spotting scopes. They asked me if they were on the right track to the 14th hole.

“Yes,” I told them. “You’re almost there. They’re even more beautiful than you think.”

MORE ABOUT MONARCHS

• Monarch Watch
• Monarch Watch’s list of California overwintering sites (1997)
• The Xerces Society
• Journey North
• Entomology Today (for multiple articles, search: “monarchs”)
• 2014 Berkeleyside story on annual butterfly counts
• Book: “Chasing Monarchs: Migrating with the Butterflies of Passage” (Yale University Press, 2014) by Robert Michael Pyle

HOW TO BE MONARCH-FRIENDLY

• Don’t spray herbicides or pesticides.
• Grow nectar plants that butterflies prefer.
• If you’d like to grow larval (“host”) plants, consider native milkweeds.

Special thanks to Andy Gilbert for suggesting this colorful story — and to Professor Shapiro, Mia Monroe, Alan Kaplan, Rusty Scalf, Juan García, Bill Shepard, and John Greenleigh.

Elaine Miller Bond is photographer for “The Utah Prairie Dog: Life Among the Red Rocks” (University of Utah Press) and author of “Dream Affimals” (Sunstone Press) and “Affimals” (LIT Verlag). Look for her forthcoming board books, “Running Wild” and “Living Wild” (Heyday Books).

See more of  the stories Elaine Miller Bond has written for Berkeleyside about local wildlife.