The other day, as I was slowly coming to my senses after a good night’s sleep, I heard a collared dove cooing outside my window. To keep myself from being lulled back to sleep by its soporific calls, I started counting how many times in succession the bird called “to-doo-doo”.
9 … 7 … 9 … 11 … 9 … Then suddenly – 3. A few minutes later, the long sets of cooing started up again. And again ended abruptly after just three! What was happening? Why such a drastic change in rhythm? Then it hit me: both times, an airplane had passed overhead!
The poor dove had given way to the superior boom of human invention. Unable to hear itself calling for a mate, the bird simply had to keep its mouth shut until the competition passed.
A collared dove sits on high perches to communicate loud and clear. Photo: Aron Tanti
Raising the pitch
Birds, I found out, are being affected so badly by human noise that there are reduced populations of birds around the noisy places where we live and work.
Some birds have even adapted their song pitch to a frequency higher than the average human sounds, in their efforts to hear each other communicating.
As we go about our din-filled day, we pay little attention to the steady decline of natural sounds. After all, the orchestra of human noise has surrounded us since birth and we are oblivious to the harm it is causing nature – and us.
“The orchestra of human noise has surrounded us since birth and we are oblivious to the harm it is causing nature – and us”
Higher, constant noise levels are associated with higher levels of stress, less offspring, shorter lifespans, sleeping disorders, nervous dispositions, tinnitus and chronic anxiety.
Noises trigger “stress response” – a reaction that allows us to escape danger. But this response comes at a price in our chronically noisy society, as the constant release of stress-response hormone builds up in our bodies, affecting our brain and immune functions. Even as we marginalise birds by out-competing them in the sound department, we shoot ourselves in the foot.
A Kuhl’s pipistrelle flying over the Għadira Nature Reserve echolocating undisturbed by loud sounds. Photo: Victor Falzon
Clicks and squeaks
The animal we most obviously associate with sounds is the bat, whose legendary echolocation has even spawned a superhero character.
Bats’ hearing is so sensitive that they can hone in on a mosquito in pitch dark. One piece of kit that will help you see just how how much our noises are affecting nature is a bat-detector. This nifty device, not much larger than a mobile phone, can translate bats’ supersonic squeaks into clicks and squeaks our ears can hear.
Teach your child to listen to nature. Go for an evening walk, around dusk, and turn on your bat detector. Discover which combination of elements are guaranteed to fill your ears with a cacophony of bat clicks.
Street lights close to gardens or fields attract the night-flying moths that sleep among leaves during the day. Your bat detector will allow you to “see” the feeding frenzy going on above you as bats pick off thousands of moths, mosquitoes and beetles in an evening.
“Our head is too cluttered with our own sounds to realise we are drowning nature out”
Turn it down
But turn your detector towards a passing car and pick up the ultrasonic racket car tyre friction makes over tarmac. Like birds, bats cannot hear themselves over our din. Together with pesticides, our noisy lives are driving them to the brink, as we invade more and more dimensions of their lives. This is a reality that few of us are aware of, as our head is too cluttered wth our own sounds to realise we are drowning nature out.
The same stresses are happening at sea, where the sonic boom of our vehicles is confusing the natural pattern of vibrations that fish and other creatures depend on to understand and map their surroundings.
Reduce your family’s dependence on motorised methods of fun at the beach. Turn the volume down. Enjoy the sound of silence that hits you as you plunge under the waves and spend quality snorkelling time with your child. Focus your attention on each wave washing up on the shoreline and follow the shifting sounds as it gently sinks into the sand.
Fish like this two-banded sea bream hear by picking up vibrations through a lateral line running along their bodies. Photo: Desirée Falzon
Sanity and survival
One of the best things we can do to give nature ground is to be aware of our noise level. Spend time in nature with your child without your gadget comforts. Be really aware of your surroundings and what lives there.
Keep your ears headphones-free and mobile phone-free when in nature and listen. Your children will have better hearing than yours, so play the listening game and see how many nature sounds you can pick out.
Notice how birds don’t just “chirp” – they call, sing, chatter, squabble, warble… Wind moves leaves differently depending on the leaf size, position, frequency… Water rushes after heavy rain but streams bubble, rough waves roar against rocks but lap against the shoreline.
Notice sounds you never realised like snails crackling over dry leaves. Play word games with your child to describe what you’re hearing.
Giving ourselves and our children space to listen to nature sets both on a course to better health. For us, it is sanity. For nature, it is survival.
Desirée Falzon is a naturalist and field teacher with BirdLife Malta.
Waves go through a range of sounds as they ebb and flow on a sandy beach. Photo: Desirée Falzon
