New Class of Insecticides Linked to Bird Declines, Researcher Asserts

In a new book, a Dutch researcher says the introduction of a new class of insecticides two decades ago has led to a steady decline in bird species that rely on insects as their main source of food. Henk Tennekes, of the Experimental Toxicology Services in Zutphen, the Netherlands, says the widespread use of a potent new group of insecticides, called neonicotinoids, has led to a drastic decline in insect populations, which, in turn, is causing declines in bird populations in Europe. In his book, The Systemic Insecticides: A Disaster in the Making, Tennekes says neonicotinoids are placed inside seeds and permeate the entire plant, leading to the death of any insect that feeds on a crop treated with the insecticide. “The evidence shows that the bird species suffering massive declines since the 1990s rely on insects for their diet,” said Tennekes. Such species include house sparrows, common swifts, and starlings, whose populations have shown significant declines in recent decades. Some scientists believe the use of neonicotinoids is one reason behind the recent collapse of bee populations in Europe and the U.S., but others said far more study is needed before researchers can conclusively prove that neonicotinoids are a key cause of insect and bird declines.