A wild fox broke into the Smithsonian's National Zoo outdoor flamingo habitat overnight, killing 25 American flamingos and one northern pintail duck, the zoo announced.
Three other flamingos were injured and are currently being treated at the zoo's veterinary hospital. The flock originally included 74 flamingos.
Staff arrived at the outdoor flamingo habitat early Monday morning to find the dead birds. The staff said they sighted the fox, but it escaped.
"This is a heartbreaking loss for us and everyone who cares about our animals," said Brandie Smith, director of the Smithsonian's National Zoo and Conservation Biology Institute. "The barrier we used passed inspection and is used by other accredited zoos across the country. Our focus now is on the well-being of the remaining flock and fortifying our habitats."
The outdoor exhibit is regularly checked multiple times a day by staff. During the last check on Sunday at 2:30 p.m. everything was fine, according to the zoo.
But after the incident, zoo staff found a new softball-sized hole in the metal mesh surrounding the yard. The mesh has since been reinforced, live traps were set around the outdoor yard, and digital camera traps with infrared sensors were set up to prevent future attacks.
The remaining flamingos have been moved indoors to their barn and the ducks to a covered, secure outdoor space.