Woodpeckers Feeding on Emerald Ash Borers

Woodpeckers might be the answer to the growing problem of emerald ash borers in the U.S., a new study has found.

The study, conducted by researchers at University of Illinois at Chicago, found that woodpeckers are feeding on the pest.

The Emerald Ash Borer (Agrilus planipennis) or EAB is an invasive beetle species whose larvae bore through the ash trees, disrupting the flow of water and nutrients.  EAB has already destroyed millions of ash trees in the U.S and Canada.

Researchers said that a native insect fighter such as the woodpecker is better than using chemicals to kill the pest. Chemicals are expensive and can damage the environment.

In the current study, the team wanted to find whether bark-foraging birds such as woodpeckers and nuthatches were feeding on ash borers or not.

For the study, researchers sought the help of schoolchildren from Dempsey Middle School in Delaware. The team asked the kids to monitor pest and woodpecker activity in the area.

A section of the woodland was cut down for examination each year. The students were asked to find and paint all holes in the bark of the tree. EABs have a distinctive way of boring through the tree; they carve through the bark to create a serpentine gallery. Students used different colors to paint large holes made by the woodpeckers, crescent-shaped holes made by EABs and small holes made by other insects.

When the bark was stripped for examination, students could identify whether the bird had eaten an EAB or other insect.

"This was looking at woodpecker foraging at a fine tree-by-tree scale," Charles Flower, UIC postdoctoral research associate in biology and first author of the study, according to a news release.

The study showed that woodpeckers were eating about 85 percent of the pests in an infested tree.

The kind of predator response accounted by the Delaware school-kids is called 'functional response,' when a creature adopts strategies to find and kill its prey.

There is another type of predator-response to a new food source- called the numerical response. In this response, scientists usually see a larger number of the predator in the area.

A related study at Cornell University has found that the population of woodpeckers and nuthatch is increasing in Detroit and around the Great Lakes,

"Woodpeckers won't save a tree once it's infested, but they may save the forest. Or at least save a nearby forest," said Flower in a news release.

The study is published in the journal Forest Ecology and Management.                                        

EAB was first discovered in southeastern Michigan near Detroit in the summer of 2002. The insects probably came along with wood packing material via ships or planes from Asia.