By Rachel Tennenbaum
When their wings are shut together, monarchs look a bit like dead leaves. Clustered together on a eucalyptus branch, they can be hard to see. They’re there, though, without fail, and on a warm fall day the eucalyptus grove by Natural Bridges State Beach is alight with orange butterflies.
The state preserve is the only one in California, and a large part of Santa Cruz’s identity. Visitors come from all over the world; on a Saturday one can hear at least six different languages spoken in one afternoon. Couples walk together, children run down the wooden platform to the grove, and there are always at least two photographers camped out with arm-length lenses.
Eight-year-old Shayna Mabanag came from San Jose with her family to visit the butterflies.
“I’ve been here a bunch of times,” Mabanag said. “It’s fun watching them and seeing what they do, watching them fly by and everything.”
The monarchs, who are tropical butterflies, fly west to winter on the California coastline. In Santa Cruz they flock to Natural Bridges State Beach, where the eucalyptus grove they call home is recognized as a state preserve. The area is quiet, with a wooden viewing platform where one can observe the clusters of monarchs perched on the tree branches.
Visitors to the monarch grove are as numerous as ever — last year alone there were 3,000 people— but the butterfly population itself seems to be falling.
“Ten years ago there used to be 150,000 butterflies every year,” said Barbara Cooksey, an interpretive specialist at Natural Bridges State Park. She points to photographs a decade old, where the clusters of butterflies are so thick that the leaves of the trees are completely obscured. “Last year they peaked at 10,000,” she said. Cooksey also added that the monarchs have been returning home earlier in the year.
When asked why, Cooksey points to changing weather patterns, development and pesticides.
“Herbicides, pesticides, habitat loss and bioengineered corn and soy, because both products contain pesticides,” Cooksey explained. “The pollen will blow to adjacent milkweed and the insecticides will kill the caterpillar.”
With the recent scrutiny placed on the monarch’s distant cousin, the light brown apple moth, Santa Cruz citizens have questioned whether or not the county-wide spraying will affect the monarchs. The short answer is no.
“Sex pheromones are species-specific, because otherwise in nature it would be too confusing,” said Dr. Deborah Letourneau, an environmental studies professor at UC Santa Cruz. The pheromones, which the county is using to hamper the apple moth’s reproductive cycle, will bear no impact on the monarchs.
Letourneau had other ideas to bring up.
“One question is, how would a new herbivore that eats a lot of things indirectly affect monarchs?” Letourneau said. “If [the moths] ate milkweed, it’s bad for the monarchs. But if it ate [milkweed’s] competition, it could be good.”
The long-term effects of the light brown apple moths and the spraying remain to be seen. In the meantime, Cooksey’s advice is to eat organically and plant a butterfly garden, with plants such as milkweed and others that will attract monarchs.
“People ask, ‘what do they do?’ Because they’re not good pollinators,” Cooksey said with a laugh. “But they’re beautiful.”
_Natural Bridges State Park is open sunrise to sunset. Docent-led tours also available. Contact the State Beach at 831.423.4609._