Our neighbourhoods are falling silent as birds suffer dramatic declines in number, writes Don Knowler
A green rosella sang a tuneful melody on my return from the Sunshine Coast, where I had travelled to escape the tail-end of winter.
Together with my feathered friends, some of my other neighbours were also in tune as I made the rounds of my street to thank members of the unofficial neighbourhood watch for keeping an eye on my house, and the resident over the road who put out my bin for the refuse collection.
The notion of linking both feathered and non-feathered neighbours might seem fanciful, perhaps the result of a little too much alcohol consumed at Melbourne airport during a delay in the flight back to Hobart, but in my life avian neighbours are as vital a part of my suburban environment as the humans ones.
Such wild thoughts took on an added significance when I read a report on my return from holiday which revealed my feathered neighbours were vanishing from the streetscapes across the world.
The State of the Birds Report 2022 by Birdlife International painted an alarming picture of the decrease in bird numbers.
Globally, 49 per cent of bird species are declining with 13 per cent threatened with extinction. At least 187 species are confirmed or suspected to have gone extinct. In Australia, 12 per cent of species are under threat but the only one to vanish so far is the paradise parrot, although eight have been lost from Australia’s offshore and oceanic islands.
Agriculture, logging, hunting, exploitation of natural resources and climate breakdown are the main threats to birds worldwide. There is also the threat of competition for food and nesting sites from introduced birds and predation by introduced animals – mainly foxes and domestic and feral cats. In more recent years birds have also been colliding with manmade structures like high-rise buildings, particularly if lights are left on at night.
Listening to the melodious duet of a pair of green rosellas, and the sweet twittering of a scarlet robin, I was thankful the catastrophic decline in birds worldwide was not being replicated in the Waterworks Valley where I live, although anecdotal evidence suggests a decline in some species.
Bird lovers in suburban areas of the United States, however, are certainly noticing a feathered absence. And the silence in gardens is highlighting a problem that goes beyond just missing the beauty of birds in the countryside and gardens.
The latest report said since 1970, a staggering 2.9 billion individual birds – or 29 per cent of birds people see and hear every day – had been destroyed in North America alone.
A leading conservationist in the US state of Connecticut, Margaret Rubega, gave another perspective on the loss of birds which coincidently corresponded with my metaphor about suburbia and its birds.
“If you came out of your house one morning and noticed that a third of all the houses in your street were empty, you’d rightly conclude that something threatening was going on,” she told an American news agency when the United States issued its own state of the birds report.
Dr Rubega noted that the estimated three billion lost “neighbours” had a role to play in protecting human food supplies, by eating the insects that not only attacked crops but carried diseases that affected plants, animals and humans. Birds were also essential for seed dispersal and pollination.
In the early 1960s, scientist and author Rachel Carson warned of a world without birds in her seminal work, Silent Spring, which dealt with the effects of chemical poisoning on wildlife. Since then the impact of harmful pesticides on birds and wild animals has been largely mitigated by tighter controls on pesticides like DDT. Scientists having addressed one problem now grapple with a more widespread one – habitat loss.
The Birdlife International report squarely blames land-clearing and resultant habitat loss as the driving force behind bird decline, and the loss of fauna and flora in general. Published before the Birdlife International report, the more detailed United States survey reached the same conclusion.
The American researchers, detailing their findings in the journal, Science, projected population data using 13 bird surveys dating back to 1970 and computer modelling to come up with population trends for 529 species. These showed a near 30 per cent decline without taking into account climate change.
Especially worrying was the decline of once common species which could be seen in suburbia.
“This decline means that the environment’s not in good shape,’’ said Pete Marra, director of the Georgetown Environment Initiative and one of the American study’s authors. “We’re also seeing it in insects. We’re seeing it in frogs. We’re seeing it in marine environments. This is not good for us. It’s not good for our children or their children. We’ve got to do something to solve this problem.”
At the same time the North America report was being published came another from Asia, revealing the caged songbird trade was threatening populations of wild birds in parts of Indonesia. Scientists working on the island of Java calculated that the number of caged birds there might now outnumber those in the wild. In Java, like much of Asia, most homes have a caged songbird, the birds often used in contests to judge the best singers. Although many birds are bred in captivity, wild birds are also trapped to supply the bird trade.
The US survey, especially, struck a chord with me because it had its roots in the period I became a serious bird-watcher, buying my first pair of binoculars in the late 1960s.
At that time much of my bird-watching was confined to farmland in the rural area of Surrey where I grew up and over the past 50 years I have had first-hand experience of bird decline in the country of my birth, which to a certain extent is worse than that revealed in the US study.
Those very areas where I learned my birding have seen declines in farmland species of more than 50 per cent, with previously common birds like the yellowhammer now difficult to find.
Across all habitats in Europe, 600 million birds – 19 per cent – have vanished since 1980.
The loss of British farmland birds especially has been attributed to the advent of industrial farming, in which the weeds provide many birds – and insects – food have been eradicated, and more intense crop rotations have not given ground-breeding birds a chance to rear young.
Britain’s farmland experience is reflected across Europe – 57 per cent of farmland birds being eradicated there – and, as with what is happening in both the US and Canada, this holds a warning of what could happen in Australia if the question of vanishing habitat is not addressed.
Australia might not have the same human population pressures affecting the rest of the developed world but surveys by BirdLife Australia reveal our bird numbers are also declining rapidly, with some species like Tasmania’s orange-bellied and swift parrots facing extinction. Two migratory shorebirds visiting Tasmania, the eastern curlew and the curlew sandpiper, have also been added to the critically endangered list in recent years. The curlew’s numbers have decreased by 90 per cent.
Australian seabirds are the biggest group under threat – 43 per cent of once abundant species have declined since 2000.
It appears that birds are vanishing right before our eyes, and the researchers compiling the American report warned of complacency not just in their own backyard, but worldwide.
“People need to pay attention to the birds around them because they are disappearing,” said the US study’s lead author Kenneth Rosenberg, a Cornell University conservation scientist. “One of the scary things about the result is that it is happening right under our eyes. We might not even notice it until it’s too late.”
The Mercury, Hobart, October 31, 2022