North America's most famous butterfly is back. But will it last? After years of decline, nearly 250,000 monarch butterflies descended upon the Pacific Coast this winter. The more than 100-fold increase over the previous year's total, according to the Xerces Society for Invertebrate Conservation, offers an encouraging sign for the growing community of monarch admirers working to save the iconic insect. It's the highest tally since 2016.

But the butterfly's bumper year may not herald a long-term comeback. Insect populations can fluctuate wildly year to year. Pesticides, habitat destruction, and global warming still threaten the orange-and-black itinerant. Hundreds of other butterfly species are disappearing across the American West as the region becomes drier and hotter. Butterflies and other pollinating insects play a key role in sustaining both crops and wild plants.

But the recent monarch sightings have rekindled hope. Dozens of scientists, activists and everyday folks are planting pit stops for the western monarch as it makes its epic annual migration from as far away as British Columbia to overwintering groves on the California coast. Along the way, they hope to inch the monarch off a path to extinction.

In Oakland, California, Tora Rocha is making sure that even a crowded city can be a monarch refuge. "I realized that it wasn't just farmers and pesticides that are killing pollinators," Rocha said. "I had an epiphany in the middle of the night and said, 'Oh my God, I have to change this.' "

So as supervisor of the Gardens at Lake Merritt, Rocha planted 12,000 square feet of gardens full of milkweed, the only plant on which the butterfly lays its eggs, and other nectar-rich plants. "And then the monarch started showing up," she said. "It was very quick." Now retired, she runs a grass-roots group called the Pollinator Posse that teaches both children and adults about insect conservation.

More than 100 miles to the east in Mariposa County, Heather Bernikoff lamented the irony of how few monarchs now visit her ranch in the Sierra Nevada foothills. ("Mariposa" is Spanish for butterfly.) "Just little by little, you just don't even notice that they've gone away," she said.

As an Indigenous woman raised with "love for our planet," she knew she needed to act after reading about the monarch's decline. She planted over 1,000 plants for pollinators, fencing off about 7.5 acres. When "one gorgeous, big monarch" finally showed up a few miles from the ranch last September, she took off running. "I wanted to get a picture, and I wanted to see what it was going to land on," she said.

Deedee Soto is a biologist and pollinator conservation planner with the Xerces Society. She works with growers and ranchers in California's Central Valley to plant hedgerows of woody plants, restoring native habitat within farmlands. Helping the monarch, she said, can be good for both farmers and other wildlife. The hedgerows can also support ladybugs that prey on crop pests.

While this winter's uptick in monarchs is encouraging, she said, the population is "still nowhere near what it was in the past." A 2015 U.S. Fish and Wildlife Service report found that nearly a billion of the butterflies had vanished since 1990.

In 2020, Fish and Wildlife Service officials determined that the monarch's numbers were so low that it warranted protection under the Endangered Species Act. But the agency declined to give it federal safeguards, arguing that other species should take priority. The agency will revisit its status each year. Until then, many Californians will keep planting milkweed. "We just don't have time to wait," Rocha said. "We need to keep this momentum going."