Experts believe an invasive beetle is responsible for an increase in sightings of an elusive woodpecker species in the western Chicago suburbs. John Cebula of the DuPage Birding Club says the pileated woodpecker has been seen and heard fairly regularly for the past month or so on the east side of the Morton Arboretum in Lisle. Forest Preserve District of DuPage County ecologist Brian Kraskiewicz has reported that the species has been spotted near Naperville and other spots around the county. Experts say the pileated woodpeckers are attracted to the area's large ash trees that have been ravaged by the pesky emerald ash borer. They say the dead and dying trees provide the ideal home for the species.