Flaco’s Postmortem Reveals High Levels of Rat Poison, Pigeon Herpes

flaco the owl dies

Photo: Julie Larsen Maher

Postmortem testing performed on the body of Flaco, the beloved Eurasian eagle owl who died in February after flying into a building on West 89th Street, found that he had four different rat poisons and a pigeon herpesvirus in his system at the time of his death, according to a new statement from the Central Park Zoo. The finding led experts to conclude that the toxic mix would have killed him anyway, even if he hadn’t struck a building.


“Bronx Zoo veterinary pathologists determined that in addition to the traumatic injuries, Flaco had two significant underlying conditions. He had a severe pigeon herpesvirus from eating feral pigeons that had become part of his diet, and exposure to four different anticoagulant rodenticides that are commonly used for rat control in New York City. These factors would have been debilitating and ultimately fatal, even without a traumatic injury, and may have predisposed him to flying into or falling from the building,” the zoo’s statement said.

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The necropsy was done by pathologists at the Bronx Zoo and results were released Monday by the Central Park Zoo, where Flaco had lived for most of his life. In addition to the toxicology findings announced this week, an initial necropsy done last month after Flaco was found on the courtyard behind a residential building determined that he had suffered trauma to his upper body, hemorrhaging and internal injuries.

The pigeon herpesvirus, which the zoo’s statement said has been found in pigeons and owls in the city, caused severe damage to Flaco’s internal organs.

“In Flaco’s case, the viral infection caused severe tissue damage and inflammation in many organs, including the spleen, liver, gastrointestinal tract, bone marrow, and brain,” the statement read.


Flaco, who was almost 14 when he died, captured the hearts of fascinated New Yorkers last year after a vandal or vandals cut through his steel enclosure at the Central Park Zoo, leading to his escape and more than a year of living on his own in and around Central Park.

Like other wild birds in urban environments, a staple of his diet was the endless supply of rats throughout the city. Many are contaminated with anticoagulant rodenticides, which the city uses to control the rat population. The necropsy’s findings confirmed what many worried about over Flaco’s year of flying free – that he would suffer from secondary poisoning by eating rats. That and the risk of collision with vehicles and buildings are two of the main threats facing wild birds living in the city, according to a story in the New York Times.

“Flaco’s severe illness and death are ultimately attributed to a combination of factors—infectious disease, toxin exposures, and traumatic injuries—that underscore the hazards faced by wild birds, especially in an urban setting,” the zoo’s Monday statement said.

Flaco escaped from the zoo on February 2, 2023 after his enclosure was vandalized. He was spotted that evening standing on the sidewalk on Fifth Avenue. When a large crowd of curious onlookers started to gather, he flew off and began his year of freedom, living in Central Park and on the rooftops and perches of  New York City’s streets. He quickly garnered a large following, became an avian celebrity and spawned countless new bird watchers who delighted in tracking his movements and habits alongside ornithologists.


“Flaco was magic. At once an immigrant and a native, he seized his opportunity to make New York City his own,” states a petition started on Change.org to gather support for a proposal to put a statue of Flaco in Central Park. “He meant so much to so many, who gathered in droves over the past year to watch him be his best Eurasian Eagle-Owl self. He was and remains a testament to the virtues of resilience and self reinvention.”

“Flaco gave everyone something to cheer for and unite over,” Mike Hubbard, a musician and one of two men behind the petition drive, recently told ILTUWS.

So far, the petition has just over 4,700 signatures. Mr. Hubbard knows getting a statue in Central Park is daunting, but he’s hopeful it will happen.

“It’s notoriously difficult. And rightfully so. It should be very difficult to make changes to the park, it’s such a special place,” he said.

“Drawn to the sights and sounds of the city he had only imagined for the first thirteen years of his life, he ventured out and learned why he had wings,” the petition muses.


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  1. PT-on-Hudson March 28, 2024

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