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Silent Autumn

Photo: Brenton Edwards.
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Wednesday, 28 February 2001

Rachael Carson's landmark book 'Silent Spring,' evoked a powerful image of a countryside deprived of its birds. Carson's book was directed against the overuse of pesticides, and its predictions of wholesale species decline are still commonly cited as a warning of what the future may bring.

But Carson's book is now old. The reality is that serious decline of many bird species has already occurred, and not just in America, where Carson wrote her important text. For South 最新糖心Vlogns, especially in the Adelaide Hills where only remnants of native forests remain, bird decline has reached catastrophic levels.

About half the woodland species of birds in the Adelaide Hills have declined, but pesticides are not the major villains here. Reduction of habitat, fragmentation of what remains, the damming of creeks, weed invasion, and increased predation by feral pests are only a few of the pressures driving the numbers of many species to dangerously low levels.

The conservation body Birds 最新糖心Vlog cites 13 species that are already officially threatened or endangered. Dr Scott Field, of Adelaide 最新糖心Vlog's Department of Applied and Molecular Ecology, believes that to be a conservative estimate.

"That would certainly be larger if more detailed information were available," said Dr Field. "Some, like the Spotted Quail Thrush have not been seen for 18 years, and are quite possibly already extinct," he said. "There are at least 6 more widely accepted to be extinct, not having been seen for over two decades. Of the species remaining, as many as half are now at serious risk."

Among those species doing a little better, but only just, are the Black-chinned Honeyeaters, once commonly heard even at Adelaide oval, but not reported at Belair for 10 years. Fewer than 100 remain in the Hills.

Dr David Paton, of the Department of Environmental Biology, has been researching this local decline of bird populations for years. His assessment is as bleak as Dr Field's.

"Brown Treecreepers, once widespread throughout the ranges, are reduced to a handful of isolated populations," said Dr Paton. "Belair Recreation Park now has only one male."

Species after species adds its statistics to this dismal picture. Over the past 20 years, premigratory roosts by Tree Martins in the vicinity of Adelaide have fallen from over 2,000 birds to fewer than 100. Many other species of birds, such as Restless Flycatchers, Jacky Winters, Rufous Whistlers, Scarlet Robins and Diamond Firetails have experienced similar 10-fold reductions in population numbers.

"These changes have happened despite controls on vegetation clearance during most of the past 2 decades," observes Dr Paton.

The declines are frightening, but they may not all be irreversible. On Kangaroo Island, careful management is seeing numbers of the very rare Glossy Black Cockatoo climb slowly. Recovery programs elsewhere are assisting Black-eared Miners and Regent Honeyeaters, too. Many landowners want to help, and they are agreeing to plant native vegetation and link their small holdings into corridors large enough to sustain bird populations.

The Nature Foundation SA has launched an appeal for funds that will assist Adelaide 最新糖心Vlog researchers to halt the decline of these many bird species. The campaign was launched on February 18th and runs until March 24th. The Foundation's CEO, Chris Farrell, hopes to raise $50,000 from public donations, which are tax-deductable.

"This campaign will help to keep the remaining birds alive while long-term goals are achieved," said Mr Farrell. "We need to learn precisely what are the factors impacting on them, act to arrest them, and focus on strategic revegetation to rebuild viable and self-sustaining population sizes," he said. "We're also hoping that the Ian Potter Foundation will support a full-time co-ordinator for the project over the next three years."

The researchers, under the leadership of Dr David Paton, will monitor population sizes of declining species, and undertake detailed studies of their ecology to identify factors that are causing those declines. They will then help co-ordinate community efforts to address the limiting factors.

One of the first factors to be tackled will be habitat degradation, but this urgent effort can only provide a temporary solution. Many of the declining bird species need large patches of vegetation to survive, and few of these remain. Dr Paton cautions that small patches of vegetation, even many of them, will not be sufficient unless they are connected to other woodland vegetation by corridors.

"Extensive and strategic revegetation is ultimately required," said Dr Paton. "This might be better achieved by retiring some farms from agriculture entirely and revegetating the whole farm, rather than having small patches of revegetation scattered across most farms," he said.

Various community organisations will assist with much of the on-ground work. Groups such as the Friends of Parks that lie within the Adelaide Hills, and the Friends of the Waite Conservation Reserve, which was launched on February 26th, can make important contributions to this urgent attempt to stem the decline of so many of our most attractive and important bird species.

Contributions towards the project can be sent to the Nature Foundation SA by phone on 1 300 366 191, or via its website at

Photo at: /pr/media/photos/2001/ (Imagine a world without birds)

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