In late May, a mysterious illness began killing songbirds in Washington, DC, Maryland, and Virginia. Cases were then found in nine additional states (Delaware, Florida, Indiana, Kentucky, New Jersey, Ohio, Pennsylvania, Tennessee, and West Virginia). The symptoms of the disease include blindness or crusty eyes, lethargy, confusion, and head shaking. Scientists from a number of state and federal agencies are attempting to diagnose the illness. Although officials have not tied the spread of this illness to bird feeders, some did recommend that feeders be taken down temporarily. (Regardless, when in use, feeders should be disinfected periodically.)