ST. PAUL, Minn. (WCCO) — More Minnesotans went deer hunting than previous years, which means more eagles had access to deer remains left behind.

As a result, The Raptor Center in St. Paul said they’ve been busy with eagles suffering from lead poisoning.

READ MORE: Derek Chauvin Sentencing: Legal Expert Thinks Ex-Cop Will Get At Least 25 Years

Lead-based ammunition is sometimes found in gut piles, and many eagles use those remains as a food source.

“Eighty-five to 90% of the eagles that come in have some amount of lead in their system,” said Dr. Julia Ponder.

RELATED: DNR’s Much-Loved EagleCam Makes Its Return

It’s a common diagnosis at The Raptor Center. From the beginning of deer hunting season through January, Ponder will see 30 or more eagles suffering from lead poisoning. Due to the brain damage caused by ingesting lead, most of them don’t make it.

READ MORE: HCMC Awarded For Focus On People Experiencing Homelessness

“We had more young eagles, hatch year or first or second year eagles, come in with lead toxicity and they came in earlier in the season,” said Ponder. “It’s such a fixable problem. It’s something we don’t have to do to our national bird.”

Gut piles left behind in November stick around long after hunting season. Which is why it’s common to see a spike in lead poisoning in eagles when the snow begins to melt.

“And then in the spring, when all the snow melts, then these gut piles become fresh again. And they are exposed because the snow has all melted and then the eagles start eating that and there is still lead there. It’s still toxic,” said Lori Naumann, DNR nongame wildlife representative.

In some parts of the state there isn’t enough snow right now to cover the remains of deer killed by lead ammunition. Which is why Naumann is asking hunters to think about using copper-based ammunition in the future.

“The price has gone down significantly for copper shots,” said Naumann. “Eagles actually learn. They can hear that gun shot and they’ll follow that gunshot to where the hunters have left a gut pile.”

MORE NEWS: MN Supreme Court: ‘The Time Is Right’ To Evaluate, Possibly Expand Audio/Video Coverage Of Criminal Proceedings

The DNR said one theory on why more younger eagles are being treated for lead poisoning is because, overall, the population in Minnesota is strong right now, meaning more birds are scavenging across the state.

John Lauritsen