Four eagles dead in Delaware

A bald eagle flies along the Fox River in South Elgin on Tuesday, February 16, 2016.

Four bald eagles died over the weekend in Delaware after being found about 30 miles from where 13 eagles were found dead last month in Maryland.

One of the eagles was found dead Saturday near Dagsboro, Delaware, wildlife officials said. Three more died after attempts at resuscitation failed, the state's Natural Resources police said.

Those three eagles were part of a group that was found disoriented in a farm field in Sussex County, Delaware, about a mile from where the first dead eagle was discovered, Delaware authorities said.

The cause of death is not known. Delaware Natural Resources police said they were actively investigating but declined to comment on possible causes.

Authorities have said poison may have caused the deaths of the eagles found last month near a farm in the Federalsburg, Maryland, area.

The U.S. Fish and Wildlife Service has been investigating and has said they did not result from natural causes. However, no specific cause has been determined.

Federalsburg, on the Eastern Shore, is about five miles from the Maryland and Delaware border and is northwest of the Dagsboro area.