The bird was discovered by Esteban Salamanca, who spotted it hopping through his neighbor's yard. He grew concerned when the eagle was still there after he had gotten ready for bed, according to the humane society.

The organization dispatched two licensed wildlife rehabilitators, who observed that the eagle was struggling to breathe. Laboratory tests later confirmed severe lead poisoning.

X-rays revealed that the eagle had swallowed fragments of a manufactured object. Staff members could not identify the fragments but said they may have come from fishing tackle or ammunition.

"It's a good reminder that leaving spent ammunition or tackle in the environment can have unintended and devastating consequences for wild animals," the humane society said in a statement.

The death underscores a persistent and preventable threat to Wisconsin's bald eagle population. Lead poisoning is a leading cause of death for the birds, which scavenge on carcasses and gut piles left behind by hunters, or ingest lost fishing tackle. Even tiny amounts of lead can be lethal, causing neurological damage, respiratory distress and starvation.

Bald eagles were removed from the federal endangered species list in 2007, but they remain protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act. Wisconsin's population has rebounded in recent decades, though wildlife advocates say lead exposure continues to undercut recovery efforts.

The humane society urged residents to properly dispose of spent ammunition and fishing gear, and to consider non-lead alternatives when hunting or fishing. The organization did not say whether the eagle's remains would be tested further or whether the case would prompt any enforcement action.

Salamanca could not immediately be reached for additional comment Tuesday evening.