But it was the book’s allegorical title that stuck with people. Imagine a world in which the singing of birds — that immemorial, irrepressible harbinger of spring — faded year by year into silence, the birds gone and so too the insects, the amphibians, the bats and wolves and whales, all the familiar voices of nature. All muted by human meddling. That world is increasingly becoming our own. Despite Carson’s entreaties, we have continued, by and large, to treat the natural world as if it were “for the birds ”— useless until proven otherwise, until some sort of profit can be derived from it. If nothing else, a bottomless dumping ground. Carson imagined birds, in their taciturnity, as striking a death knell for the planet, mutely signalling the end. Thus it is to birds that we should look if we are to grasp the scale of our profligacy, the categorical errors in our judgment.

Birds are the most conspicuous non-human animals. Most sing and call, or perch out in the open, or flit about during the day; some sport gaudy plumage and carry out their birdy business in plain sight of humans. Carson was right in referencing birds in her allegory — most everyone can relate in some way to them.

And birds are everywhere on this planet. They inhabit arctic tundra and steamy jungle and everything in between. Many species migrate seasonally from place to place. Nine major migratory “flyways” have been identified on our planet, stretching from pole to pole and spanning nearly every continent, together circumnavigating the globe.

But birds the world over are in trouble. According to a recent report from BirdLife International, one in eight bird species is threatened with impending extinction. Seventy-seven percent of those threatened live in forests, which are disappearing similarly fast: According to the Food and Agriculture Organization of the United Nations’ 2012 “State of the Forests” report, “[over] a period of 5,000 years, the cumulative loss of forest land worldwide is estimated at 1.8 billion hectares – an average net loss of 360 000 hectares per year…Population growth and the burgeoning demand for food, fibre and fuel have accelerated the pace of forest clearance, and the average annual net loss of forest has reached about 5.2 million hectares in the past ten years.”

Things asea look no brighter. Many coastal species, like Atlantic Puffins, are struggling to cope with the sea changes wrought by warming and ocean acidification. Others, such as the critically endangered Tristan Albatross, have seen their remote island redoubts completely overrun by ravening introduced species.

A recent Audubon study concluded that 314 North American bird species are imperiled by shifting, shrinking habitat ranges, caused either by climate change or other anthropogenic means. Some, like the Great Plains-dwelling Baird’s Sparrow, stand to lose more than 95% of their range by 2050.

On top of all this, humans are (still) killing birds indiscriminately for sport, subsistence, or out of blithe ignorance. And once a species is threatened with extinction, the end can come swiftly. Vultures in Asia have disappeared apace in ten years’ time. More than 70% of crane species are at risk of vanishing within the century. And we’d do well to remember the plight of the once-innumerable passenger pigeon, utterly decimated in a generation of wanton avicide. Since 1500, more than 150 bird species have gone extinct (that we know of), every one a victim — either directly or indirectly — of our strivings.

Because birds are ubiquitous, intertwined with our global existence, their silence is telling. As far as phylogeny goes, the vertebrate class Aves — to which all birds belong — serves as a plain-to-read barometer to the global ecosystem. They are our eyes in the sky, under the sea, intimating a bird’s-eye view of the world. Guiding us, as albatrosses guided mariners in days of yore. As that old cliche has it, birds represent the feathered embodiment of freedom and maneuverability: to be “free as a bird”. If even they can’t escape climate change, what can?

The plight of birds needn’t be a swan song, though. There’s been plenty to celebrate along the way — California Condors and Peregrine Falcons being two stand-out examples of successful, human-driven recovery — but every celebration comes with a caveat. As Rachel Carson wrote so presciently in 1962, “Nature has introduced great variety into the landscape, but man has displayed a passion for simplifying it. Thus he undoes the built-in checks and balances by which nature holds the species within bounds.” In other words: We are sliding down a slippery slope, and there’s no telling where we’ll end up.