Silent Spring: Chapter 8 Summary & Analysis

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.

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.

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.

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.

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.

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.

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.

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?