New Canaan, a wealthy town in Connecticut, is a town of lawns.
Lawns, green and rolling. Lawns, trim and bug-free, lined with sculpted shrubs. Lawns, like so many lawns across suburban America, sprayed with pesticides each spring, mowed each week of summer and raked free of leaves each fall.
But Bill and Mary-Ellen McDonald have taken a different approach. They have lived in their yellow house here for more than 50 years. Over time, they started letting wildflowers grow. Bunnies appeared. Birds came back. Soon, they realized they were creating a sanctuary.
A sanctuary, specifically, for fireflies.
“These fireflies are here, and really only here,” Mr. McDonald, 75, said on a recent Friday evening, the sky fading to lilac. “This is an island in the sea of lawn chemicals.”
Suburban sprawl is destroying their habitat: The insects spend most of their lives in the soil, which is threatened by development. And pesticides are killing them off.
“Fireflies are like most other wildlife: They need things a little wild,” said Candace Fallon, a conservation biologist and one of the creators of the Firefly Atlas from the Xerces Society, an international invertebrate conservation group.
For ecologists, fireflies are good ambassadors for broader environmental causes like the dark sky movement, a campaign to reduce light pollution, and “no-mow May,” an anti-lawn credo. The insects are enchanting, even nostalgic. They flash like morse code messages from childhood, the Tinkerbells of the longest days of summer.
“I think of them sort of as the gateway bug,” said Sara Lewis, a leading firefly expert at Tufts University. “They’re a way of getting people who may not otherwise be that interested.”
Some people have created public spaces for the insects, which Dr. Lewis said inspired “firefly tourism.” Parts of Asia have large firefly populations. Many fireflies also live in the Great Smoky Mountains, in Tennessee. The Pennsylvania Firefly Festival is another destination.
But few people have created firefly oases on their own properties. Fewer still open up their homes to host firefly viewing parties, as the McDonalds have done every summer for the past 30 years.
Dozens of people gather over several evenings during peak season — from June to mid-July. Ms. McDonald, 74, makes ice cream sundaes with homemade fudge sauce by the half-gallon. Mr. McDonald uncorks champagne.
“Some people used to bring their children,” he said. “Now, they bring their grandchildren.”
They let the children catch fireflies, and even let them take their new friends home in jars for just one night. The next day, they return to release them, often with hand-drawn firefly drawings in tow.
Mr. McDonald’s interest in fireflies started when he was young. In recent years, he helped create a public firefly sanctuary, which is part of the New Canaan Land Trust. (It has gotten so popular that it now requires nightly reservations during peak firefly season.)
But even as Mr. McDonald, a retired investment banker, has invested time and significant financial resources in creating havens for the fireflies, few of his neighbors have done the same.
Yellow pesticide signs peek out of front lawns, warning dogs to keep off the grass. A buzz-cut of grass rolls to the property line, its edges razored by landscape crews. Floodlights abound.
“Some people are basically lawn people,” Mr. McDonald said. “Do they care about the fireflies? The answer is ‘no.’ It’s just not on their radar. It’s just not part of the culture.”
That’s the point of the parties, which are a hyperlocal type of environmental activism. One night with the fireflies; maybe one lawn without chemicals.
The demonstration worked for Michele Murray Sloan, a real estate agent who has lived in New Canaan all her life. She said she first visited the McDonalds’ home a few years ago and noticed the difference.
“The house next door had a sign that said ‘pesticides,’ there were no fireflies,” she remembered. “We were like: ‘Whoa, it’s almost like there’s this invisible gate right there that the fireflies know not to go past.’”
Ms. Sloan stopped using pesticides after that.
“Every single year, it feels like we have more fireflies,” she said of her own home, adding, “It makes you aware that even just on your own property, not using pesticides makes a difference.”
As the sky slipped from lilac to indigo and the trees became blurs, Mr. McDonald pointed out the different species. (He can tell them apart just by their light patterns, their flight paths.)
There goes a Comet. Oh, look, a Femme Fatale. (You can see her — there. She’s flying horizontally.) By the trees, those are Heebie Jeebies. That one’s a Big Dipper. See it? Right there. See the way it blinks?
Chris Schipper, the chair of the New Canaan Conservation Commission and a former president of the land trust, was there that evening. He caught a firefly, cradling it gently.
Then, he opened his hands. It jackknifed its wings open, and flew away.
“To see several thousand fireflies, lighting up the sky, right in your backyard?” he said. “I think it slows you down and makes you think: ‘Maybe a perfect lawn isn’t as magnificent as something like this.’”
As the humans on the porch drained their champagne flutes, the unwitting insect activists bobbed in the air. They blinked — on-on-off; on-on-off-on-on-off — trying to find a mate before their own little lights sputtered out for good.