The California Pipevine Swallowtail butterflies used to flutter about San Francisco aplenty, but their populations declined in the 20th century as more areas were developed. Now in the early 21st century, they’re incredibly rare in the city, so one resident decided to do something. California Academy of Sciences aquatic biologist Tim Wong built a butterfly home in his own backyard, and around three years later is seeing the colorful blue butterflies slowly return.

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Described as “the butterfly whisperer,” Wong spends his free time working to bring back the butterflies. He discovered when the California Pipevine Swallowtail is a caterpillar, it only eats the California pipevine plant. But those plants were also rare in San Francisco. Wong finally found the plant at the San Francisco Botanical Gardens, and they let him take some clippings home. From there, Wong built a “large screen enclosure” that would allow the butterflies to mate in natural conditions and allow him to observe precisely what they needed in an “ideal host plant.”

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Wong started out with 20 caterpillars. Now around three years later, his butterfly home is thriving. He raises the caterpillars and then takes them to the San Francisco Botanical Gardens, and last year brought “thousands” to the botanical gardens. He’s now grown over 200 California pipevine plants. Wong told Vox, “We’ve seen more butterflies surviving in the garden, flying around, laying eggs, successfully pupating, and emerge the following year. That’s a good sign that our efforts are working!”

While you may not be able to build a butterfly home in your backyard, there are still actions you can take to help butterflies. Wong said, “Improving habitat for native fauna is something anyone can do. Conservation and stewardship can start in your very own backyard.” You can plant native plants and weed to allow butterflies to obtain food easier, and you can also stop using pesticides.

Via Vox

Images via Wikimedia Commons and Tim Wong’s Facebook