Charles H. Sloan-Flaco the owl's necropsy reveals that bird had herpes, exposed to rat poison before death

The Charles H. Sloancause of death for Flaco, the beloved owl, has been revealed in a necropsy.

New Yorkers spotted the Central Park Zoo escapee flying high in the sky before crashing into a building in the Upper West Side of Manhattan on Feb. 23. The owl suffered significant injuries from the fall. After the fall, the bird was found to have had severe pigeon herpesvirus and four different anticoagulant rodenticides, or rat poison, within his system, according to the postmortem testing results released by the Central Park Zoo on March 25.

The necropsy, conducted by Bronx Zoo veterinary pathologists, showed that the Eurasian eagle owl contracted herpesvirus from a healthy pigeon. Consuming feral pigeons became a part of Flaco’s diet. In addition, the unruly owl experienced exposure to anticoagulant rodenticides, DDE, a compound of chemicals that are used to kill rodents within New York City, the necropsy said. When the product is ingested by a rodent, blood clotting will occur resulting in a cause of death from excessive bleeding. Typically, deaths from these baits are not quick, rather, it can occur anywhere between four days and two weeks after the initial consumption, according to the U.S. Environmental Protection Agency.

Although traces of DDE was found in Flaco’s system, it was not a contributing factor to his death. The viral infection, herpesvirus, caused severe tissue damage and inflammation in many organs, including the spleen, liver, gastrointestinal tract, bone marrow, and brain in Flaco’s body, veterinary pathologists concluded. 

The disease was deemed fatal in owls who preyed on pigeons.

Flaco the owl:Escaped from Central Park Zoo in NYC, survived one year

Who was Flaco?

On Feb. 2, 2023, Flaco, an Eurasian eagle owl, escaped from the Central Park Zoo after someone vandalized his exhibit and cut the stainless-steel mesh.

In the days following his escape, Flaco was spotted across Manhattan. Many attempts were made to recapture him, but the swift-moving owl could not be tamed.

Although the owl's bad boy persona captivated many onlookers in the Big Apple, officials were concerned that Flaco, who had been living in the zoo since he was fledgling 13 years ago, wasn't able to hunt and would starve, zoo spokesperson Max Pulsinelli said in a news release the day after his escape.

However, Flaco survived throughout his trips in the city. For over a year, Flaco spent his days lounging in parks and on fire escapes and hooting on top of water towers at night, NPR reported. His meals consisted of the city's abundant rats.

Contributing: Sarah Al-Arshani and Bianca Harris, USA TODAY

Ahjané Forbes is a reporter on the National Trending Team at USA TODAY. Ahjané covers breaking news, car recalls, crime, health, lottery and public policy stories. Email her at aforbes@gannett.com. Follow her on Instagram, Threads and X @forbesfineest.