"The feces of a lead poisoned bird are often bile-stained - bright green in colour. Wings may droop and birds may also appear listless.":
"Even small amounts of lead can cause serious problems for wild birds; a single piece of shot or a single bullet fragment has been known to kill fully grown eagles and condors. And birds that do survive poisoning may experience problems with their immune function, leading to a slow death by disease or starvation."