How one man repopulated a rare butterfly species in his backyard

The California pipevine swallowtail butterfly is a wonder to behold.

It begins its life as a tiny red egg, hatches into an enormous orange-speckled caterpillar, and then — after a gestation period of up to two years — emerges as an iridescent blue beauty. Brimming with oceanic tones, the creature’s wings are considered by collectors to be some of the most magnificent in North America.

For centuries, the California pipevine swallowtail — or, Battus philenor hirsuta — called San Francisco home. As development increased in the early 20th century, the butterfly slowly began to disappear. Today it is a rare sight.

But one man's DIY efforts are starting to bring the butterfly back.

His story reminds us that we can all contribute to conservation efforts — sometimes even from our own backyards.

As an aquatic biologist at the California Academy of Sciences, Tim Wong rarely has a dull day.

Whether he’s hanging out with an albino alligator, swimming with Javanese stingrays, or treating a hungry octopus to a hamster ball full of shrimp, Wong is constantly caring for one of the science museum’s 38,000 animals.

But outside of work, the 28-year-old devotes the bulk of his free time to raising butterflies, a hobby he picked up as a kid.

"I first was inspired to raise butterflies when I was in elementary school," Wong says. "We raised painted lady butterflies in the classroom, and I was amazed at the complete metamorphosis from caterpillar to adult."

In an open meadow near his home, Wong spent his days catching, studying, and raising any butterflies he could find.

Years later, he learned about the pipevine swallowtail — which had become increasingly rare in San Francisco — and he made it his personal mission to bring the butterfly back.

He researched the butterfly and learned that when in caterpillar form, it only feeds on one plant: the California pipevine (Aristolochia californica), an equivalently rare flora in the city.

"Finally, I was able to find this plant in the San Francisco Botanical Garden [in Golden Gate Park]," Wong says. "And they allowed me to take a few clippings of the plant."

Then in his own backyard, using self-taught techniques, he created a butterfly paradise.

"[I built] a large screen enclosure to protect the butterflies and to allow them to mate under outdoor environmental conditions — natural sun, airflow, temp fluctuations," he says.

"The specialized enclosure protects the butterflies from some predators, increases mating opportunities, and serves as a study environment to better understand the criteria female butterflies are looking for in their ideal host plant."

Though the California pipevine butterfly had nearly disappeared in San Francisco, it was still common outside the city, in places with more vegetation. With permission, Wong was able to source an initial group of 20 caterpillars from private residences.

He carefully transported them to his backyard and set them loose on the plants to feed.

"They feed as a little army," he says. "They roam around the pipevine plant from leaf to leaf, munching on it as a group."

Once situated, the caterpillars began their long, drawn-out process of maturation.

After about 3-4 weeks, a caterpillar pupates and forms a chrysalis (or outer shell). The insect liquifies itself inside, and either develops into a into butterfly in about two weeks, or stays dormant for up to two years (this delayed development is called "diapause").

"It’s like a long hibernation," says Wong. "And when it’s over, they emerge as adult butterflies."

Typically the adult pipevine butterfly hatches from its chrysalis in spring, but it can be seen flying from February to October. Depending on temperature, predation, and food availability, the butterflies live for two to five weeks.

During this time, the females lay tiny red eggs on the pipevine plants. Wong carefully collects these and incubates them indoors, away from natural predators like spiders and earwigs.

"From there," he says, "the cycle continues."

When the eggs hatch and a new cycle of life begins, Wong raises the caterpillars at home, then brings them back to the San Francisco Botanical Garden’s "California Native" exhibit.

While other conservationists have succeeded in repopulating the pipevine butterfly in the neighboring counties of Santa Cruz and Sonoma, none have been successful in San Francisco. In the late 1980s, a woman named Barbara Deutsch had attempted to reintroduce the species with 500 caterpillars, but the butterflies vanished after a few years.

When Wong first started bringing caterpillars to the botanical garden, he’d only transport a few hundred at a time. But as his backyard caterpillar population grew, he was able to exponentially increase this. Last year he introduced "thousands" of caterpillars to the garden.

Wong attributes his success largely to the favorable habitat he's created for the caterpillars. In the past few years, he's cultivated more than 200 California pipevine plants. Through extensive weeding, and the planting of additional nectar plants, Wong has been able to reintroduce the butterfly to San Francisco for the first time in decades.

"Each year since 2012, we’ve seen more butterflies surviving in the garden, flying around, laying eggs, successfully pupating, and emerge the following year," he says. "That’s a good sign that our efforts are working!"

While Wong has had success raising native butterflies at home, he cautions that it "isn’t for everyone." A DIY conservation effort requires a special understanding of each species' natural history, a natural sensibility, and a lot of tedious work.

But there are much simpler ways to contribute. The flourishing of local species is largely driven by restoring native habitats. Planting native flora host plants is an effective way to boost endemic butterfly populations. Weeding (to allow easier access to food sources) and avoiding pesticides is equally beneficial.

"Improving habitat for native fauna is something anyone can do," Wong says. "Conservation and stewardship can start in your very own backyard."

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