Officials probe mysterious bald eagle deaths in Utah

FILE - A bald eagle takes flight from a tree overlooking the Kootenai River near Bonners Ferry, Idaho. (AP)

SALT LAKE CITY – The number of bald eagles that have died recently from similar symptoms in central-northern Utah is up to five — and Utah wildlife officials are fearful the total may be as high 13.

Utah Division of Wildlife Resources spokesman Mark Hadley said Thursday that a fifth eagle found in Weber County died this week in a rehab center in Ogden. A sixth eagle discovered in Davis County is there with the same head tremors the dead ones had, he said.

An additional seven eagles were found dead in the same two-week period — and wildlife officials fear they may have all died from the same cause, Hadley said. They won't know for sure until tests are done, however, because nobody saw if these eagles had the tremors before dying.

Thousands of bald eagles migrate to Utah each winter, with many gathering at the Great Salt Lake where there's plenty of carp to eat in freshwater bays. The recent rash of deaths has raised serious alarms in Utah.

"I don't ever recall having this many eagles die in such a short period of time," Hadley said. "It is very unusual."

Utah State University is expected to have preliminary results early next week for the first four eagles that died at the rehab centers, Hadley said. That should provide some clues to help solve the mystery illness.

It could be encephalitis, which is caused by West Nile Virus, though officials said it seems too late in the year for that. They don't think they were killed on purpose.

To find out what killed the other seven, wildlife officials sent the majestic birds to a lab in Madison, Wisconsin It could take up to a month to get the necropsy test results back due to a backlog there and because it takes longer over the holidays, Hadley said.

The dying birds have all been discovered since the beginning of December and were found in four different counties: Weber, Box Elder, Tooele and Utah.