The Core

But it’s not just a concern for insects; 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. Because most of the insecticide applied to a seed comes off in the soil—and because neonics are both highly persistent in the environment and easily soluble in water—they are increasingly ubiquitous in many rivers, streams, and lakes, harming populations of emergent insects on which aerial insectivores like swallows, swifts, and flycatchers depend. Not surprisingly, many ornithologists see a link between pesticide use and the fact that grassland birds, the group that may be most directly exposed to agricultural pesticides, have declined by more than half since 1970.