The 'New DDT' Is Starving Out Songbirds

The list of vanishing songbirds in North America is astonishing.

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Jul 10 2014, 3:38pm
Sparrows feeding. Image: San der vanderwell/Flickr

First the collapse of bee populations and now the stunning decline in bird numbers in North America and Europe are being linked to a new generation of insecticides called neonicotinoids, a poison 5,000-10,000 times more toxic than DDT.

It turns out that neonicotinoids may be starving insect-eating birds into oblivion through indiscriminate killing of insects—including those nowhere near farm fields, a study published in Nature yesterday reports.

Insects are big part of many birds’ diets, especially when they’re raising offspring. Dutch researchers linked the steady decline of 9 of 15 insect-eating birds—like warblers, skylarks, sparrows, and starlings—to the introduction in the late 1990s of imidacloprid, the most commonly used neonicotinoid. They found that the regions with heaviest levels of this nerve poison in soil and water had the biggest declines in bird numbers that eat and rely on insects during the breeding season.  

Neonicotinoids are systemic—meaning that corn, soy, wheat and other seeds treated with the insecticide will incorporate the nerve poison into the plant itself: its roots, leaves, stem, pollen, nectar and sap. But only 5 percent of this nerve poison ends up in the plant, according to another report in Nature. Approximately 1 percent is blow away as dust during planting, leaving all the rest in the soil and soil water where the chemical accumulates and readily washes into waterways.

Eating a single corn kernel can kill a songbird.

Neonicotinoids are also taken up by roots of plants in hedgerows or woods near farm fields which makes them toxic to non-pest insects including beetles, moths, butterfly caterpillars, grasshoppers and many more. These chemicals are also likely killing flying and other insects that spend part of their life cycle in contaminated waterways.

After 20 years of increasingly widespread use it should not be surprising “there is now evidence that neonicotinoids are having broad effects through the food chain,” the study says.

In North America the list of vanishing songbirds is astonishing. In the last two decades we’ve lost between 50 and 90 percent of the kingbirds, warblers, whip-poor-wills, nighthawks, swifts, swallows, martins, flycatchers and more. Of all birds that eat flying insects, 85 percent are in decline.

Nearly every corn plant in America contains neonicotinoids said Cynthia Palmer, Pesticides Program Manager at American Bird Conservancy.

“Eating a single corn kernel can kill a songbird,” Palmer told me. The conservancy has called for a ban on using these chemicals to coat seeds.  

Neonicotinoids last a long time and can be found everywhere in the environment. And they’re used on crops even though they aren’t needed most of the time, she said.

“We’re practically sterilizing our waterways and landscapes of insects that birds and other wildlife depend on.”

Starvation may not be the only impact of neonicotinoids, both Nature studies acknowledge.  Simply eating insects contaminated by the nerve poison may have lethal and sub-lethal effects. As reported on Motherboard a new landmark study of neonicotinoids, also known as neonics documented extensive sub-lethal impacts on bees, butterflies, spiders, earthworms, birds and possibly us.

Even at extraordinarily low levels neonics have impacts on many species,” said Bonmatin, the lead author of the WIA analysis, which will be published as a series of articles in the peer-reviewed journal Environment Science and Pollution Research.

At non-lethal levels, exposure to these nerve poisons can screw up nervous systems. The documented impacts include impaired sense of smell or memory; reduced fertility; altered feeding behaviour and reduced food intake; difficulty in flight and increased susceptibility to disease and altered tunneling behaviour in earthworms. Hardest hit by all this is not bees, contrary to popular belief, but worms, and other invertebrates that live in the soil, the study found. 

Neonicotinoids are also widely used to spray fruits and vegetables, and in garden and public areas.  

The Obama administration recently told the Environmental Protection Agency to review the impacts of these insecticides on bees and other pollinators. The EPA has 180 days to report. 

Asked about whether the review will change anything Palmer replied: “What can I say that is diplomatic?….Let’s wait and see, but I’m not holding my breath.”