New report highlights threat of ‘neonics’ to birds


By Tom Gilbert

Sixty years ago, Rachel Carson’s groundbreaking book “Silent Spring” detailed the devastating impacts of the pesticide DDT on bird populations.

DDT was especially harmful to species at the top of the food chain, like bald eagles, whose egg shells became so thin that they cracked in nests before chicks could develop. Populations plummeted as nesting pairs repeatedly failed to produce young.

“Silent Spring” is credited with launching the modern environmental movement, as well as leading to a nationwide ban on DDT. Bird species slowly began to recover.

The DDT ban spurred the chemical industry to develop alternative insecticides, including a class known as neonicotinoids, or “neonics” for short. They were touted as being safer for birds and animals.

It wasn’t long, however, before neonics came under criticism for harming pollinators, including domesticated honeybees, butterflies and wild native bees.

Neonics affect insects’ nervous system, causing paralysis and death. In 2018 the European Union banned the use of three common neonics on field crops, although there are some exemptions.

A new report by naturalist and author Scott Weidensaul points to neonics as the most likely cause for declining numbers of farmland birds and grassland birds – including many found in New Jersey, such as bobolinks, savannah and field sparrows, many species of swallows, and kingbirds.

In “Neonic Nation: Is Widespread Pesticide Use Connected with Grassland Bird Decline?” the author presents compelling evidence that neonics may be at least as harmful as DDT.

The article appears on the Cornell Lab of Ornithology website, All About Birds.

Weidensaul notes that the advent of neonics seemingly allowed an overall reduction in pesticide use on the U.S. landscape. But the numbers, he said, do not take into account the single biggest use of neonics: as coatings on seeds for farm crops, to make the plants toxic to nibbling insects.

“Because of a loophole in federal pesticide regulations, seed coatings are not even considered ‘pesticides,’ and their use is neither tracked nor directly regulated by the U.S. Environmental Protection Agency,” he writes.

Most corn planted in the United States, and a significant percentage of soybeans and other crops, are treated with neonics.

If scattered during planting, these seeds can be lethal to birds.

“If swallowed, a neonic-treated kernel of corn is enough to kill a jay-sized songbird, and as few as four pinhead-sized canola seeds, treated with neonics, can cause a host of sublethal effects in a sparrow-sized bird, interfering with avian metabolism, migration, fat deposition and reproduction,” he writes.

Even when not swallowed by birds, neonic-coated seeds have serious environmental impacts. Because most neonics applied to seeds come off in the soil – and because they are highly persistent in the environment and easily soluble in water – the chemicals have found their way into many rivers, streams and lakes.

There, they kill populations of not only many beneficial insect pollinators, but huge percentages of the emerging insects that birds like swallows, swifts and flycatchers depend upon for food.

“Without an abundant food supply, bird populations cannot be sustained,” said Dr. Emile DeVito, New Jersey Conservation Foundation’s staff biologist. “The neonic threat is more nuanced than the cracked eggshells caused by DDT because it is incredibly hard and expensive to track and measure factors like fewer eggs, lower juvenile bird weights, or songbird death during migration due to malnutrition.”

Weidensaul has pored through years of scientific papers and interviewed scientists to gather evidence that neonics are indeed harming grassland birds and farmland birds.

“Not surprisingly, many ornithologists see a link between pesticide use and the fact that grassland bird populations, the group that may be most directly exposed to agricultural pesticides, have declined by more than half since 1970,” he writes.

Ken Rosenberg, a retired Cornell Lab conservation scientist, told the author that scientists must dig deeper into how pesticides and other factors are driving bird declines.

He suggested a study focusing on the house sparrow, a species that may be uniquely suited as “bio-sentinels” because they are abundant around farmland.

Several states, including New Jersey and New York, are already working to reduce or to eliminate neonics in order to protect pollinating insects and the food chain.

In New Jersey, Gov. Phil Murphy signed the “Save the Bees” bill in January, following the lead of several other states.

New Jersey’s action is a good first step, as the law limits neonic pesticide applications in New Jersey’s non-agricultural settings such as gardens, lawns and golf courses.

But neonics are still allowed for agricultural uses and are incredibly widespread in New Jersey’s most prevalent forms of agriculture – growing corn and soybeans.

In 2021, the New York State Legislature introduced the “Birds and Bees Protection Act,” a bill that, in addition to banning neonics for residential use, would for the first time in the United States prohibit the sale of seeds treated with neonics.

The bill passed the New York State Assembly during the spring of 2022, but it still requires action by the New York State Senate.

As New York moves toward banning neonic-coated seeds, New Jersey should do the same. The issue certainly merits swift action for the health of pollinating insects, birds, our waterways and food supply.

Tom Gilbert is a co-executive director of the New Jersey Conservation Foundation, Far Hills.