Frog Songs
Why citizen scientists are volunteering to listen to amphibians
Why citizen scientists are volunteering to listen to amphibians by Caitlin Stall-paquet
It’s an hour after sunset, one night in early April, and I’m standing on the side of a dirt road in my hometown of Frelighsburg, Quebec, with my hands cupped around my ears. I’m listening for the calls of anurans — amphibians without a tail, so frogs and toads. I am here, more specifically, to hear the croaks of wood frogs, which are one of the first species to peek their little brown heads out after a long winter of hibernation.
This isn’t just recreational listening, mind you — this is also for science. I am a volunteer observer, one of several who are gathering data about dwindling amphibian populations in this region. For the parcours d’écoute (“listening pathways”) project I am on, participants each choose a quiet eight-kilometre stretch of road and go out listening along it, noting the frog and toad species they hear and the volume of their calls, returning to record these observations in the same spots once more, later in the season, ideally year after year. It’s called the Amphibian Population Monitoring Program, a long-term citizen-research project created in the 1990s by the Saint Lawrence Valley Natural History Society — part of a provincial-government push that came about when the International Union for Conservation of Nature highlighted worldwide declines of amphibian populations.
I make my path along Chemin Pinacle, at the foot of the mountain of the same name, stopping at markers every 800 metres and perking up my ears for a three-minute stretch at each one. This road is about three kilometres from the house I grew up in, where my bedroom was next to a pond that resonated with an amphibian chorus through the spring and early summer; on warm nights, I would leave my window open and be lulled to sleep by frog songs.
Though the term “citizen science” is relatively new, the practice of nonscientists gathering data about the natural world is not. Sometimes this has been undertaken by curious individuals: Mary Anning, who had no training, hunted for fossils along the cliffs of Devon, England, in the early nineteenth century and unearthed the first known plesiosaurus skeleton. (She is also believed by many to be the inspiration behind the “She sells seashells by the seashore” tongue twister.) By the early twentieth century, evolving telescope technology allowed the astronomically curious to turn an eye to the sky and gather useful data. But, increasingly, groups have also coalesced to pursue scientific interests. The National Audubon Society founded the Christmas Bird Count in 1900; it is one of the longest-running community science projects in the world. In 1954, a sea turtle survey began on a single beach in Japan; now, about forty beaches across the country host counts. And the University of Cape Town’s Animal Demographic Unit established an ongoing project to monitor population dynamics in 1991.
In Canada, the federal government launched its Naturewatch website in 2000, encouraging citizens to monitor all sorts of wild elements, from plants to ice formations to frogs. And, in the last decade, apps like inaturalist and Merlin and online databases like ebutterfly have bolstered community participation in natural sciences by allowing users to easily share their findings about the locations of animals, identification of species, and number of individuals in a sighting. Nearly all of us now own devices that put scores of wildlife information at our fingertips. Databases are growing — in a boon for underfunded scientific communities, findings on apps are shared to data repositories like the Global Biodiversity Information Facility — and long-term monitoring projects made up mainly of volunteers, like the one I am participating in, are gaining popularity.
Nowadays, amateur scientists have extra impetus for heading into the field: studies like the major UN report on biodiversity last year, which warned of unprecedented declines in the natural world and estimated that 1 million plant and
animal species are now at risk of extinction. Increased tracking of these accelerated declines is key to understanding, and hopefully slowing down, what scientists call our planet’s ongoing sixth mass extinction. Without filling in our knowledge gaps about the natural world, we can’t know what it is we’re trying to save. I n 1968, musician Bernie Krause and his collaborator, Paul Beaver, were contracted by Warner Brothers– Seven Arts to make an album on the theme of ecology. Beaver refused to head out into the wild to capture sounds, but Krause got hooked on the experience. In 1970, he and Beaver released In A Wild Sanctuary, the first album ever to use natural soundscapes, and in the years that followed, Krause would help pioneer a new field: soundscape ecology — the study of the sounds of a land- or seascape.
Sound is an important indicator of an environment. “The sounds of the natural world, when they’re in a healthy habitat, come across as a kind of orchestration,” Krause, now based in Glen Ellen, California, tells me. “In order for the birds to be heard, they have to stay out of the way of the frogs, out of the way of the insects, and so on. . . . All animals vocalize in a relationship to one another, much like instruments in an orchestra.” He later coined the term biophony to describe this effect of the collective sounds of the creatures in a habitat. To date, Krause has recorded over 1,200 habitats; in the years since he began this work, the sounds in nearly half of them have become compromised or gone silent. At times, Krause has returned to the same spot to capture stark human-caused environmental changes, finding near silence in spaces once loud with birds, frogs, and insects.
Animals make sounds for many reasons: to communicate fear or danger, alert others that they’ve found food, indicate their availability for mating, or warn another member of the species that they’re on their turf, among others. For anurans, vocalizations aren’t just about males letting females know they’re looking to get busy; they’re a form of group self- defence. As the voice of each individual joins in, it becomes harder for predators to distinguish between and locate them. But, when that chorus shrinks or is interrupted by loud human sounds, individuals can be exposed and put at risk.
Growing up, my pond was home to a full chorus. As the sun set in late spring, when all the species had woken up from hibernation and the mating season was at its peak, the backyard and woods became loud with the high-pitched chirp of spring peepers, the continuous trill of grey treefrogs, and the lower-midrange staccato warble of leopard frogs. I loved the quick overlapping croaks of green frogs, which sound like a cartoon character swallowing hard in an awkward situation. I spent afternoons canoeing around the pond’s banks to spot our huge resident bullfrog, who chimed in intermittently with his bass, cow-like vocalization. (I’m not being sexist with pronouns, to be clear: the majority of anuran songs we hear are males calling to females or protecting their territory.)
Krause wants to get everybody to similarly use their ears. “If [people] listen and they shut the hell up,” he tells me, “they’re going to get a different sense of the world very quickly.”
Without learning about the natural world, we can’t know what it is we’re trying to save.
L ast year, a review published in the journal Science detailed global mass amphibian die-offs partly due to the spread of the disease chytridiomycosis, commonly known as chytrid. Caused by a fungus called Batrachochytrium dendrobatidis, chytrid is now found in dozens of countries and has caused the presumed extinction of at least ninety amphibian species. (The earliest known case in North America was found in a museum, in the bodies of two green frogs collected in
Saint-pierre-de-wakefield, Quebec, in 1961.) The disease has caused the largest number of documented deaths attributable to a single illness in recorded scientific history.
Though devastating, chytrid and other diseases aren’t the sole or arguably even the main culprits of amphibian decline: illnesses find opportunity in climate-changed or human-altered habitats. Frog, toad, and salamander populations are often already weakened by displacement (like construction in the marshy wetlands they call home) or irritants (such as chemicals used in farming that act as immunosuppressants). Sara Ashpole, an environmental studies professor at St. Lawrence University, in Canton, New York, estimates that somewhere between 40 and 70 percent of North America’s wetlands have degraded or disappeared completely; in and around densely inhabited Canadian centres, that climbs to 98 percent.
In 2017, the World Wildlife Fund (wwf) published the Living Planet Report Canada, detailing population trends for 903 invertebrates, including forty-six species of amphibians and reptiles (a group called herpetofauna), half of which showed signs of decline. The wwf also reported that 42 percent of amphibians had been assessed as atrisk in 2014. According to the International Union for Conservation of Nature, herpetofauna have some of the highest proportions of threatened and “data deficient” species for vertebrates, which means there isn’t comprehensive data about baseline populations — the funding to gather the necessary information simply does not exist. Species like these often get overlooked when it comes to the allocating of resources, with money being funnelled toward the cuter, more charismatic megafauna species that pluck at human heartstrings. (I’m looking at you, pandas who are too picky about your mating partners.)
Which brings us back to interested amateurs, standing by roadsides, listening. “If we can establish baseline recordings for any environments that are calibrated to known and repeatable standards,” Krause wrote in his 2013 book,
The Great Animal Orchestra, “then the recorded information we gather will represent a collection against which future recordings can be accurately assessed.” F our weeks later, in early May, I head out for another frog encounter. On the drive from Montreal, I play various recordings of local anurans on a loop, like a favourite playlist, via an app called Frog Calls, which is meant to help users identify different species. Though there are more than a dozen living in the area, I’m mostly prepping my ears for the American toad and the spring peeper today — the wood frogs woke up four weeks ago, so they’re long past the peak of their croaking.
Before I start the official listening pathway, I go explore the muddy banks of a pond across the street from my best friend’s parents’ house. The gang is nearly all there, filling their designated positions in the layered amphibian chorus that brings me back to being a kid. Standing between the trees, the trilling peepers are so loud it almost hurts my ears. (Measuring around 2.5 centimetres, peepers are barely bigger than a paperclip, but a group of the little guys can be heard from over three kilometres away.) My friend’s father tells me their calls used to be just as deafening even up on their front porch; it doesn’t carry quite as far these days. A similar reduction in the intensity of the sounds has been reported by Cree adults in James Bay who remember the loud springs of their childhoods.
For those who have been lucky enough to find themselves in the middle of a full chorus, the loss is a tragedy: that auditory immersion, being surrounded by voices bouncing off water and leaves in the dark, is impossible to reproduce. Ashpole often speaks to young adults whose parents recall catching polliwogs and listening to roaring nighttime ponds; they have never had the same experience. To her, it’s imperative to take people into the field to transmit passion first-hand. Telling me about going out with a group one night, she recalls looking down on the ground “and there were just thousands of little [spadefoot toads], and we couldn’t step anywhere. . . . You expect kids to get really excited, but what I find more exciting is watching adult parents having a childlike moment.”
As I stand in the dark and listen intently to the frogs’ voices, what is at first chaotic comes into focus, my ears straining to separate the different types of calls. I’m pleasantly surprised by the range of amplification my hands provide as I change their shape around my ears, and I’m starting to understand the distinction that Krause makes between listening and hearing — the difference between engaging with the sense and passively experiencing it. It’s a practice that can make us realize that all is not lost and that the environment can recover if we let it — in his book, Krause points out that there are now choruses of frogs and nightingales thriving at Chernobyl.
We currently find ourselves on the other side of a stark but intangible line created by the climate tipping points we’ve blown past for and at our leisure, the virulent diseases we’ve helped spread, and the habitats we’ve destroyed in the name of peace and quiet. Being on this side of the line is a lot like grieving: we are in an “after” time. Earlier this year, I used the words “we are in the after” in an epilogue to my friend Alexandre Bergeron’s music video for “Aquatic Ruin,” a song about ecological disaster that ends on a chorus of spring peepers. And, as with other forms of grieving, in times defined by disease and mass extinction, we need to bear witness. We can be quiet and press record to capture what is still there. We can cup our hands around our ears and listen.
“The sounds of the natural world come across as a kind of orchestration.”
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