Eagles have been seen flying into trees and rock ledges. Scientists tested for pesticides and heavy metals, but found nothing. Viruses and bacteria also were ruled out. Researchers now are turning their attention to algae because Pfiesteria and some other species produce toxins that affect the nervous system. One thought is that fish and smaller birds eat the algae, and eagles get the disease by eating the birds and fish.
Eagles are solitary birds.
They're not like mallards, which are gregarious birds. So it's unusual to see several eagles dying in the same location at the same time. Hundreds of coots have died of the disease, along with an untold number of mallards and three other species of duck and Canada geese, said Miller, who has been part of a scientific team that's been studying AVM since it was first discovered. To prove that the birds weren't picking up the disease elsewhere and flying to the lakes to die, scientists clipped the wings of healthy coots and farm-raised mallards and released them on Woodlake. Most of the birds developed brain lesions within six days.