A nearly 200-year-old cemetery comes alive after dark, where the dead share space with frogs, toads, and the scientists listening to them

Late April in Cambridge, Massachusetts: a small group of people on the edge of a pond in a historic cemetery, standing near a willow tree, eyes closed, listening. They are not here to mourn. They’re here to do science, and what they listen for could help determine the fate of an entire class of animals.

According to a report by writer Cara Giaimo for bioGraphic's Field Notes series, the group was gathered at Mount Auburn Cemetery as part of FrogWatch USA, a national citizen science program managed by the Akron Zoo. Leading the local group that night was Jenni Austiff, a herpetologist at Boston University. They were to listen for frogs, record what they heard, and submit that data to a national database used by researchers tracking amphibian populations across the country.

No biology degree needed: just ears, a notebook, and a willingness to stand in the dark.


Why a cemetery? And why frogs?
Mount Auburn Cemetery is no ordinary cemetery. The cemetery, which opened in 1831, is described in its official records as occupying 175 acres in one of the most densely developed areas of North America and containing more than 5,000 trees across hundreds of species.

That makes it part of a global pattern. According to a review titled ‘Biodiversity potential of burial places: A review on the flora and fauna of cemeteries and churchyards’ published in Global Ecology and Conservation, which analyzed 97 studies across five continents, cemeteries and churchyards consistently act as refuges for rare and endangered species in otherwise heavily developed landscapes, with 140 protected taxa documented across the reviewed literature. Their conservation value, the researchers found, is rooted in something simple: they have been left largely undisturbed for a very long time. It attracts birders, naturalists, and community scientists year-round. And there is something to defend in the stillness of its ponds. It attracts birders, naturalists, and community scientists year-round. And there is something to defend in the stillness of its ponds.

Herpetologist Joe Martinez has spent more than a decade leading efforts to reintroduce native amphibians that disappeared from the cemetery, some of which disappeared as long as a century ago. The American toad, the spring peeper, and the grey tree frog are now all successfully re-established species. Every late spring, thousands of newly metamorphosed toadlets emerge from Halcyon Lake in what locals call the “Toad Jubilee,” a mass migration so significant that cemetery roads are temporarily closed to protect them.

“The American toads, the spring peepers, and the gray treefrogs disappeared from Mount Auburn Cemetery at least thirty and perhaps as many as one hundred years ago,” Martinez said. “Now they are back.”

Frogs are in crisis; here's what the science says
That comeback story is significant because frogs are not doing well globally. ‘Ongoing Declines for the World's Amphibians in the Face of Emerging Threats,’ a 2023 study published in Nature, found that nearly 41% of all assessed amphibian species are currently threatened with extinction. That’s a higher proportion than for mammals, reptiles, or birds. The study, which assessed more than 8,000 species for the IUCN Red List, found that climate change was the primary driver of declines in 39% of species from 2004 to 2022, followed by habitat loss (37%).

Chytridiomycosis, a fatal fungal disease caused by the pathogen Batrachochytrium dendrobatidis, is also imperiling frogs in the United States. According to the same Nature study, disease, along with climate change and habitat destruction, is among the central forces pushing amphibians closer to the edge. Because frogs are sensitive to environmental change, the decline in frog populations is widely viewed as an indicator of the health of wetland ecosystems more generally.

What citizen scientists are actually doing
According to FrogWatch USA, volunteers are trained to identify the calls of particular species of frogs and toads, then go out into the field at night between February and August to listen and record at a specific wetland site. They record the species heard, temperature, wind speed, and calling intensity. That data is entered into a publicly available national database, and researchers analyze it to monitor population trends and guide conservation strategies. The Akron Zoo says the program now has more than 130 active chapters in 38 states and Washington, D.C.

The work is not always glamorous. That night at Mount Auburn, the group mostly heard distant traffic and ambulances. But then, near a small pond, a spring peeper called out, then another, then a few more, pinging calls back and forth across the water. One volunteer noted, “Peeper level 2.” Limited data. But real, cumulative, meaningful data.

Why this matters for you right now
So what’s the honest case for getting involved? This is one of those rare moments where regular participation, say, a few evenings a season, at a pond or wetland near you, really does add to research that professional scientists could not do alone.

No gear or science background needed. The training is free. Real researchers use the data. And standing quietly in the dark while something ancient and small calls back at you is harder to describe than you'd expect.

According to FrogWatch USA, you can find your nearest chapter and sign up at the Akron Zoo’s website. If you're anywhere near Cambridge, the Mount Auburn Cemetery chapter is actively expanding its volunteer base, and if recent reintroduction efforts are any indication, the ponds there are only going to get louder.

The frogs are waking up. Someone needs to be there to hear them.