During a recent early morning walk around the Ashumet Holly Wildlife Sanctuary in East Falmouth, a group of Eastern bluebirds were found feeding on the berries of an oriental bittersweet vine. The brightly colored bluebirds are very dependent on berries during the winter. Bluebirds are beloved songbirds with a soft melodious call. They have bright blue upperparts, chestnut brown throat and breast, and a white belly.