Monarchs Get the Royal Treatment

A peaceful plot of land stretches south from the corner of West Estudillo Avenue along San Leandro Blvd, opposite BART, between the sidewalk and a massive mural depicting the migration of the Monarch Butterfly. The larger-than-life images invite their fluttering counterparts to take a rest below in the San Leandro Butterfly Garden.

In the fall and spring, migrating monarchs (Danaus plexippus) avail themselves of this beneficent gift, a respite they rightly deserve. Although scientists estimated the Western United States monarch population at a healthy 247,000 at the end of 2021, that number had dipped precipitously low to an estimated 2,000 only as far back as 2020. This astonishing and inexplicable rebound testifies to nature’s resilience, yet for all that, the U.S Fish and Wildlife Service (FWS) has observed a steady decline in monarchs since 2000 and is currently scheduled to list the species as endangered in 2024.

Butterfly Garden volunteers Douglas
Spaulding, Stefanie Pregel,
 and designer, Lary Huls.

Some people are trying to help. “About six years ago,” says retired landscape architect and designer of the Garden, Lary Huls, “a guy from the breakfast club I attend saw the unkempt plot while waiting for BART one day and asked me if there was something we could do. I drew up the design, and he found the money.” Huls had centered his landscape business on native plants and saw the opportunity to provide a habitat that would support not only migrating monarchs, but other important pollinators, including numerous other butterflies, moths, birds, and bees.

Monarchs cannot fly in temperatures below 55 degrees Fahrenheit, so every October as temperatures drop, they leave their homes in the Rockies of Canada and the U.S. to wend their way south on thermals and air currents. Western US populations travel to eucalyptus, pine, and cypress groves along the California coast from Mendocino south to San Diego, while Eastern US monarchs travel various routes through Texas into Central Mexico. Though the butterflies complete the southern journey in a single generation, the trip back in the spring requires three to four generations. In a miracle of nature, the knowledge of the way back is passed on from parent to caterpillar. The parents do not make the entire journey back; rather they lay eggs along the route. The resulting caterpillars rely entirely on chemical messages received at birth. Astonishingly, these instructions survive the pupation process in which caterpillars turn into mere drops of liquid in the chrysalis before emerging as adults.

Crucial, then, to the monarchs’ survival is the availability of safe breeding environments, a resource under pressure. Threats include changes in breeding habitat due to conversion of grasslands to agriculture, urban development, widespread use of herbicides, logging, drought, and changing seasonal cues due to climate change.

While the majority of migrating populations can be found stopping over elsewhere than the East Bay (such as Natural Bridges in Santa Cruz), the garden does draw visitors. In San Leandro, Huls planted native California species such as milkweed, sunflower, and coyote mint. The milkweed is crucial as the females lay their eggs upon them alone. When emerged, the caterpillars eat the milkweed, ingesting the plant toxins. Though harmless to the caterpillars, these chemicals impart to them a taste that hungry birds avoid. The selection of plants, for Huls, has another purpose, as well. “It’s a demonstration,” he says, “that water-saving and habitat-supporting gardens can be beautiful.” Having evolved in the drought-prone Mediterranean climate of Northern California, such natives not only need less water than many non-natives but have also evolved alongside many animal and insect species as part of their life support systems.

Such gardens may be the future of pollinator conservation. Dr. Doug Tallamy’s 2020 book Nature’s Best Hope: A New Approach to Conservation that Starts in your Yard discusses the benefits of a network of conservation minded gardens with the health of local wildlife as its prime mission. An estimated 20 million acres could act as “corridors of habitat” that would collectively comprise what Tallamy calls the Homegrown National Park.

Though the butterfly problem garners broad support from the Fish and Wildlife Service and the US Department of Agriculture has a stake in the success of pollinators, given their extreme importance to the majority of our food crops, the efforts of private citizens and non-profit organizations are crucial. Citizen scientists are volunteering their time across the US to collect the data organized research requires. The Monarch Larvae Monitoring Project, for example, at the University of Minnesota monitors larval monarch populations and the milkweed they feed on. Volunteers can get involved at https://monarchjointventure.org/mlmp. You can also report your butterfly sightings at Journey North  https://journeynorth.org/sightings/.

The garden is open year-round, but if you’d like to help tend and keep it clean, volunteers are welcome on the first Saturday of every month.

San Leandro Butterfly Garden Monthly Work Day

West Estudillo and San Leandro Blvd (opposite BART)

First Saturday of every month (summer and fall)

10:00 a.m. – 12:00 p.m.

https://www.sanleandro.org/Calendar.aspx?EID=1281