The discovery of 13 dead bald eagles at a farm in Carolyn County in the state of Maryland has sparked a federal investigation. According to authorities, this is the largest case of die-offs of eagles in the region within the last 30 years.

Initial investigation on the carcasses of the animals showed no signs of trauma. This then led investigators to believe that the bald eagles may have died due to poisoning.

According to the Maryland Natural Resources Police or NPR, the eagles could have consumed an animal carcass that died from ingesting poison.

"What happens is that when farms have rodent problems, landowners will put poison to control it, and the eagles will eat the poisoned animals," NPR spokesperson Candy Thomson said according to NBC News.

To help speed up the investigation, the U.S. Fish and Wildlife Service is offering a reward of $10,000 to anyone who can provide any relevant information on the die-offs.

The NPR first responded to the scene after receiving a call from a resident who came across four dead bald eagles on a farm. After scouting the area, officials from the agency discovered nine other carcasses.

According to Thomson, three of the dead birds were already mature, which was characterized by the white feathers on their heads. On the other hand, two of them were just about to reach maturity while the others were still young, The Washington Post has learned.

Thomson noted that this is the worst case of bald eagle die-offs to occur in Maryland for the past three decades. To make matters worse, the three mature birds could have greatly contributed to the country's population of bald eagles due to their mating capabilities.

"It's been 30 years since we've seen anything like this involving this many dead bald eagles," she said in a statement. "Three mature eagles, the ones we all love that look like the national bird, are gone."

"It's sad that we have three eagles of mating ability that have been eliminated from our population," Thomson added.