Lots of signs can point to bad luck — a black cat crossing your path, walking under a ladder, breaking a mirror. But dead bald eagles falling out the sky? Now that has to mean something. 

For one farm on the eastern seaboard in Maryland, it was quite a bad omen to find 13 dead bald eagles last week. A hunter searching for shed antlers spotted two and notified wildlife authorities, who found nine more. 

State officials as well as a non-profit group are offering a $10,000 reward for any information leading to what might have caused the birds’ death, but it’s not entirely clear whether a crime was even committed. No signs of foul play were discovered such as bullet wounds or other trauma. 

No longer on the list of threatened or endangered species since the 1980s, it still remains a federal crime to kill a bald eagle. Not to mention it represents a symbol of freedom and American patriotism.

The working theory behind the deaths is that the birds may have eaten rodents that local farmers poisoned as a means of control. The poison could then travel into the birds, causing their deaths. 

Investigators were going door-to-door this week in the area about two hours east of Washington DC in attempts to determine the source. 

“It’s definitely of concern,” U.S. Fish and Wildlife Service spokeswoman Catherine Hibbard told the Baltimore Sun.