This story is part of Bird Week 2023, in celebration of Orion’s newest anthology, Spark Birds. You can preorder this book, packed with some of Orion‘s greatest essays about all things feathered, right here. On sale August 15.
BUZZES, CHIRRUPS, AND TWITTERINGS, patterings and flutterings symphonize a terrain’s biophony. And similar to landscape ecology, soundscape ecology maps these acoustics in surround sound—especially the thrum of trills, arpeggios, peeps, cheeps, hoots, and rattles composed from the beaks of birdlife. Whether it’s the chorus of pipits or pufflegs, flickers, or silky-tailed nightjars, spotted babblers, white-rumped trillers, warblers, or laughingthrushes, birdsong adorns the air we breathe, modulating the very timbre of place.
“There’s a broad relationship between bird species’ richness and abundance, and soundscape complexity,” reflects Simon Butler, an ecologist from the University of Anglia in the UK. “As you get a richer community or more individuals, the sounds they generate become richer and more diverse.”
To visualize the melodic arrangement of a habitat, soundscape ecologists, like Butler, translate bird calls into vibrant frequency bands on a spectrogram chart. In this way, they can capture the unique signature of an airy bobolink or bright song sparrow or plaintive red-throated loon, and how they interact.
“In a full, healthy community, species evolve to occupy different niches of acoustic space—so they’re not shouting over the top of one another.” Butler says. Imagine a stage set for an orchestra, with musicians in every seat playing different string, brass and woodwind instruments. “Unfortunately, as we lose individuals and species, gaps in the spectrogram start to appear.”
Because feathered communities are so integral to their environments, changes in their acoustic maps can reveal patterns in the local ecosystem’s health long before we can measure them with our own tools. To clock whether a particular habitat is degrading, maintaining, or recovering, we need only compare its soundscape at two points in time.
But, as Butler points out, “the soundscapes that I experienced, and you experienced, in our childhoods—we don’t have recordings of that.”
In this absence arises what’s known as “shifting baseline syndrome” – essentially the assumption from each generation born into a particular environment that what they’re experiencing is typical. For example, with nearly 3 billion North American birds lost since 1970, and 600 million European birds since 1980, what many children relish today as a usual amount of birdsong, adults know is riddled with hollow stretches of aching silence. And what we remember as a healthy dawn chatter for a meadow or prairie or rainforest, our grandparents would say had already degraded since their time, and so on.
This “environmental generational amnesia” means each following generation unknowingly absorbs a diminished “new normal” in birdsong: We can’t perceive how much things have changed around us, and—more importantly—what might even be possible to restore.
To begin the work of recovering a sense of baseline, Butler, along with Catriona Morrison and an international team of researchers, devised a study that took annual bird count numbers, generated by citizen scientists through the North American Breeding Bird Survey and the Pan European Common Bird Monitoring Scheme, and used them to reconstruct soundscapes from over 200,000 sites from the late 1990s and again about twenty years later. For each location, they started with a blank, five minute sound file and layered in clips of bird calls at random time-stamps and volumes to reflect the number of individuals vocalizing throughout the habitat at different distances. Though not exact replicas, the composites approximate historical soundscapes across North America and Europe.
Tune into the changes between 1998 and the late 2010s:
Location Coordinates: 52.128640, 0.97894783
Port St. Lucie.
Location Coordinates: 27.2364427, -80.5471555
Location Coordinates: 41.5295757, -120.1718519
Memory and sound both orient us to our surroundings and help us navigate the unknown. As can be heard, resounding shifts captured by the clips expose a stifling, pervasive hush that has fallen alongside declining bird populations.
“But,” says Butler, “there are a few sites that are doing well–even increasing. Using the data to understand local landscape features that are supporting increasing soundscapes is really useful in conservation management moving forward.”
Another way these soundscapes help is in projecting different sonic futures based on fluctuating climate predictions, as bird ranges and migrations shift with temperatures.
Though it can be hard to keep our ears open to our changing environments, we must stay connected to our habitats—for their restoration hinges on our collective recollection.
“Get out and appreciate today’s soundscapes,” urges Butler. “Draw comfort from them. Find time to just sit and listen.”