That sound you hear in a New York park might not be a police siren, but the cry of a redtail hawk. The rush of wind on Brooklyn's waterfront often is louder than the breath of traffic. The lonely howl of a coyote sometimes replaces the roar of commuter buses in suburban New Jersey. Wild turkeys haunt the semi-suburban lawns of Cape Cod.
The kinder side of the deadly COVID-19 pandemic and related lockdowns has been a reduction in noise across the world, and some consequent relief to the wildlife—including the human variety—that ordinarily suffer from the out-of-control sounds that our economies and lifestyles generate.
A microphone placed at the normally busy corner of Lafayette and Fourth Streets in Manhattan recorded a five-decibel drop—a reduction of 130 percent—in traffic noise levels during the recent lockdown, according to one NYU study.
The same is true of the more general human noise that registers across the planet and is measured at seismic stations, sound labs created to pick up earthquakes and other digestive rumbles of the planet.
According to a survey by Belgium's Royal Observatory in Brussels, human-caused noises, as measured by seismographs, have declined globally by 50 percent during the pandemic.
Because excess noise triggers stress hormones such as cortisol—a quarter of Europe's population usually suffer excess noise levels sufficient to trigger hormone levels that in turn lead to 900,000 cases of hypertension and 10,000 preventable deaths per annum—the recent reduction in overall noise may help mitigate the spike in people's stress quotient caused by lockdown, unemployment, and worry.
The reduction in human hyperactivity, of which the fall in sound levels is part, certainly seems to have liberated wildlife. Many of them have left their refuge, probably drawn by this pandemic-related drop in the aggressive actions of humankind, to roam cities and other places whose noise and cars they normally avoid. Thus we see mountain goats walking the town of Llandudno, Wales; wild boars in the streets of Haifa, Israel; pumas hanging out in Santiago, Chile; duck families filing across Parisian avenues; dolphins gamboling in Turkey's Bosphorus.
Ocean mammals in particular have almost certainly experienced relief from the drop in undersea sound levels associated with slowed commerce. These mammals communicate and feed by using their sensitive sound equipment, and have been increasingly stressed by noise from the thrashing propellers of merchant ships and the piercing active-sonar transmissions of naval vessels. The former, at any rate, has decreased with the reduction in ocean traffic, by fifty percent off Vancouver, Canada, according to one study.
This respite will not last. Lessons taught in hardship tend to fade quickly when the hardship vanishes, and as the pandemic recedes noise levels are bound to spike again. But for now, humans and wildlife seem to be benefiting from a rare and beneficial quiet.