Birds may control invasive insect decimating US ash trees

An invasive insect pest ravaging U.S. ash trees, the emerald ash borer, may have met its match in a native bird species, researchers say. Biologists at the University of Illinois at Chicago say woodpeckers are finding the Asian invaders a handy food source and could slow and even eventually control the pests. "We found we have a native predator that is able to detect and respond to this new rich food resource," Charles Flower, postdoctoral research associate in biology and first author of the study, said. The emerald ash borer has been responsible for the death of 30 million trees in the northeastern United States and Canada since it was first found breeding in trees in southeastern Michigan in 2002. When emerald ash borer larvae emerge from eggs laid on the tree, they burrow in and eat their way through the layer of the tree that delivers water and nutrients from root to branch, eventually starving the tree. Researchers began a study to see if native bark-foraging birds, including woodpeckers and nuthatches, were feeding on the emerald ash borer. They found woodpeckers were in fact choosing to prey on emerald ash borers, eating as much as 85 percent of the emerald ash borer larvae in infested trees in the study. Very little is known about emerald ash borer habits in its native environment, its natural predators, or how its population is controlled, Flower said, and slowing its course with the help of woodpeckers may give researchers time to learn more about how it can be controlled. "Woodpeckers won't save a tree once it's infested, but they may save the forest," he said. "Or at least save a nearby forest."