The 13 bald eagles that were found dead last month on Maryland's Eastern Shore didn't die of natural causes, wildlife officials said Thursday, and authorities are offering a $25,000 reward to help find whoever killed them, NBC News reported.
The birds showed no signs of trauma when they were found Feb. 20 on a farm and in the woods in the town of Federalsburg in what Maryland Natural Resources police said was the biggest die-off of bald eagles in the state in 30 years.
The U.S. Fish and Wildlife Service said Thursday that necropsies had also ruled out diseases, such as avian influenza, a major threat in the region because of its many poultry farms and migratory birds.
"Our investigation is now focused on human causes," said Catherine J. Hibbard, a spokeswoman for the agency, who said she couldn't release any more information to protect the investigation.