At least a dozen brown pelicans have been found dead in Mayport, and Florida Fish and Wildlife Conservation Commission officials are concerned and baffled over what's killing them.
Officials said they found the pelicans along the St. Johns River and most of them were decomposed. Only a few were in good enough shape to be tested.
Officials said there were no obvious injuries to the birds, despite a claim from a woman who reported seeing at least one bird with its throat slashed.
FWC spokeswoman Karen Parker said she fears this mass death of pelicans is a repeat of what happened in Mayport five years ago, when 70 brown pelicans were found dead.
"It was in winter. It was a very cold winter, and the birds were very emaciated," Parker said. "Like I said, we had a really big die-off then. It looks to be the same thing. A lot of the birds were there for quite some time. They had been basically reduced to just bones and feathers."
To this day, officials still don't know what killed the pelicans five years ago, but they believe the cold weather is to blame for back then and now.
It could be weeks before results from the necropsy are available.