Here, Carson returns to the symbol of silence, and to the threat of chemical “biocides” against birds, whose absence is often most acutely felt by locals. She cites local accounts from all over the country of dwindling bird populations after spraying against elm disease or fire ants, giving voice to residents who mourn the loss of the color and songs of birds.
In the book, birds function as an emblem of the loss of wildlife, symbols of nostalgia and an idyllic past that could serve to unite the public in their defense. Carson wants to give the public a voice by citing accounts from locals, reinforcing the idea that many people are concerned with the future of wild life in America.
As a symbol of this destruction, she chooses the robin, a bird whose return normally heralds the end of winter. Its springtime arrival is no longer guaranteed, however, as widespread spraying against the beetle flies that carry a fungus that causes Dutch elm disease in elm trees has decimated robin populations.
The robin is chosen partly because it is well-known and loved – Carson hopes to inspire action on its behalf, and on behalf of the previous time in which its return was as regular as the changing of the seasons. This regularity is threatened in the new world created by man.
John Mehner, a graduate student at MSU, demonstrated the causal link between spraying for Dutch elm disease and robin population drops after studying robins on the MSU campus as part of his dissertation. Sterility and death resulted from spraying, after robins ate earthworms that had ingested the poison when sprayed leaves fell in the autumn and decayed into a mulch – another example of bioaccumulation, in which poisons grow more concentrated as they move up the food chain. After spraying, Mehner found that robin populations had dropped from 370 to a mere two dozen adult birds, and no fledglings at all were found.
The careful work of biologists across the country and around the world is a key part of Carson’s book, and she celebrates their work by giving it a wider platform. The story of the elms is similar to what we have seen before; bioaccumulation allows toxins to pass up the food chain. The importance of sterility in causing population decline is re-emphasized here. The rapidity of decline is particularly troubling, since this is only one window into a problem that spans the country.
Similar studies showed that 86-88% of robins had died, while the birds’ reproductive organs were found to contain dangerous levels of DDT. This wave of deaths reached other species as well, affecting a whole chain of animals for which earthworms are a major element of their diet. Carson includes an extensive list of these birds and their qualities, those whose “wings are touched with flame” or who are “ruby-crowned.” She notes also that with the death of their natural predators—birds—insects begin to thrive, often reversing the desired effects of spraying so that the whole exercise becomes a futile one.
The language Carson uses to describe these suffering or disappearing species of birds celebrates their beauty in lyrical phrases, remembering a glorious past and envisioning a future without these beauties. Further, the sacrifice of these many-colored creatures is purposeless: because the pesticides end up killing the birds, which are the natural predators of the insects that were the intended target of the spraying, the insects end up thriving while the birds are destroyed! Insects can find a new foothold in an empty environment far more quickly than birds can.
Owen J. Gromme, Curator of Birds at the Milwaukee Public Museum, wrote to the Milwaukee Journal, reporting that accounts of dead birds were growing steadily with the pace of spraying. Locals lament that, in an attempt to save the elm, authorities have chosen a course of action that seems to destroy bird life. Surely this is a foolish bargain to strike, they suggest. Statistical evidence from Connecticut shows that spraying is not even effective at saving the elm, and New York State has had much more success with selective removal of diseased wood, or the planting of hybrid, disease-resistant species from Europe.
Again, Carson shows us a means of control that has been successful elsewhere, and which seems far preferable to the impossible choice between losing the famous American elm or the birds that live around it. Justifying the use of pesticides to save the elm is even more difficult given the lack of success that local sprayers have experienced with halting the advance of the disease, and mounting evidence of bird deaths.
The eagle, an important American symbol, is also in danger of extinction. Multiple observers show a decrease in young eagles and failures in egg-laying – data from Hawk Mountain, a bird sanctuary, and from Charles Broley on the western coast of Florida, a popular eagle nesting ground, is particularly dire. In 1947, when he began his survey, Broley found and banded 150 young eagles from 125 active nests. By 1958, he found only one young eagle after searching 100 miles of Florida coastline.
By focusing on the eagle, Carson finds a means of relating the abstract dangers of pesticide use to a specific, much beloved symbol of American patriotism. The work of on-the-ground naturalists like Broley provides the basis for her arguments about their population decline – this research exists not because anyone from the chemical industry funded testing, but because Broley had a passion.
Dr. James DeWitt’s experiments with DDT predicted this effect on bird fertility by studying quail and pheasants, and his results have been replicated by many scientists around the nation. The toxin is transferred across generations, causing sterility or early mortality in young eagles. These eagles would have come into contact with DDT because of their diet of fish, which often contain trace amounts gathered from the polluted waterways and their food supply.
The science that explains this decline in bird populations already exists, but has not been taken seriously enough by those responsible for spreading chemical controls. Eagles, like every other species in nature’s web, are vulnerable to the accumulation of toxins in their environment and food supply. And as a top predator, eagles resemble humans as an endpoint of biomagnification.
Treating seeds with pesticide in Britain led to “a deluge of reports of dead birds,” and many there see insecticides as the biggest threat to wildlife of all time. Still, as the habit of pesticide use to ‘eradicate’ pests grows, some are targeting birds directly. A group of farmers in Indiana used parathion to kill 65,000 blackbirds and starlings. Who has the right to decide, on everyone else’s behalf, that such drastic measures are necessary?
Using the documented concerns of those in other nations to suggest that lawmakers in the United States, too, should take seriously the threat of pesticides, Carson contrasts this concern in Britain with the dreadful example of Indiana farmers who chose to use parathion in an instance of direct violence against birds, rather than indirect, unpredicted destruction. Carson, again, asks why a select few, with little oversight, should have the right to make such choices that will impact everyone.