Those birds are scavengers, and they build up lead in their systems from animals shot but not harvested by hunters. "When lead projectiles hit large mammals they shatter, impregnating swaths of soft tissue as wide as three feet with toxic fragments," Williams writes. "Just one the size of a BB can fatally poison an eagle."
The University of Minnesota's Raptor Center in St. Paul received 117 lead-poisoned bald eagles during the winter of 2009-2010. Of the 46 with visible symptoms, 38 died or were euthanized, Williams reports. There have been 276 documented cases of lead poisoning in condors since 2000.
"So far 130 species have been known to ingest lead ammunition. There is no such thing as a 'safe' or 'normal' blood-lead level," Williams writes. He blames the National Rifle Association, National Shooting Sports Foundation, and Safari Club, for their lobbying against legislation to limit the use of lead ammunition and for failing to promote non-toxic steel ammo. To read the NSSF's view on lead ammo, click here. To read the entire Audubon article, click here.