The back-to-back deaths of two beloved bald eagle siblings stunned the thousands of people who tuned into the livestream of their nest in Florida. Now, biologists have shared they both died from bird flu.

In a Thursday press conference, officials from the Clinic for the Rehabilitation of Wildlife, also known as CROW, said a necropsy revealed that both eaglets tested positive for highly pathogenic avian influenza, also known as HPAI or bird flu.