So Rodríguez took it to the Wild Bird Fund, a nonprofit that rehabilitates sick, injured and orphaned wildlife. Since then, staff members had gone through “a whole arsenal” of tools to aid the ailing pigeon, including placing it inside an oxygenated enclosure and employing a plethora of dye-removal methods.

The bird was approximately five weeks old, still so young that the staff couldn’t detect its sex. It had never even had the chance to spread its wings to fly. But on Monday, Flamingo’s short life came to an end.

The cause of death: the intoxicating dye in its feathers, said Rita McMahon, director of the Wild Bird Fund. While she and her colleagues don’t know the backstory on the pink dye, McMahon said they’ve theorized it could’ve been the product of an art project or gender-reveal party gone awry.

“Flamingo was basically poisoned,” McMahon told The Washington Post. “Birds are particularly sensitive to fumes of any kind, and it didn’t help that this wasn’t any standard dye that we’ve dealt with ever before.”

It’s still unclear how Flamingo wound up in one of New York City’s most popular parks, but it “was clearly deliberately released there since it can’t fly,” McMahon said. The city’s police department is monitoring videos from the area to see if there’s evidence of animal cruelty in the recordings, she added.

After Rodríguez dropped off the king pigeon — a breed of domestic birds that are mostly bred for consumption — staffers at the wildlife sanctuary tried to remove the dye.

“We went through the whole list: mayonnaise for tar, Dawn dishwashing detergent for oil, vegetable canola oil for glues,” McMahon said.

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A staff member looked up “how to remove hair dye” and came up with a concoction of lemon juice and baking soda that was applied to Flamingo’s tail and wing feathers. It helped, McMahon said, but didn’t fully remove the dye.

“They dunked this poor bird …[It] was drenched,” McMahon added. “And Flamingo was so unstable at the time that we couldn’t just cover it with the paste, so [it] still had some of the dye in there.”

Birds’ respiratory systems are extremely sensitive, and they’re especially vulnerable to smoke, fumes and aerosols, according to the National Audubon Society. Their feathers also play an important role in the animal’s well-being, especially since their plumage is what helps them navigate the skies, shed water and keep warm. And dye of any kind interferes with these functions, McMahon said.

Birds also spend a lot of their time preening their feathers with their beaks, McMahon said. So even though the staff members managed to remove the substance from certain feathers, Flamingo was still ingesting some of it through its beak.

They dyed a waterfall for a gender reveal. An investigation followed.

During its last week of life, the bird with pink feathers became a beloved fixture at the nonprofit, McMahon said. Though the animals are usually named after the person who rescues them, Flamingo received a “creative one” as a nod to another bird with colorful feathers (albeit those get their hue from their shrimp-filled diet). Four staffers aided him around-the-clock — to no avail.

Flamingo deteriorated quickly. It was already malnourished when it was taken under the Wild Bird Fund’s wing, but it kept vomiting and becoming weaker. Through it all, the nonprofit posted updates about Flamingo’s condition on social media — sparking “unprecedented attention” and a flood of well wishes for the ailing bird, McMahon said.

On Tuesday morning, however, Flamingo’s caretakers discovered the bird’s lifeless body inside its enclosure.

Still, McMahon said there’s a lesson to be learned from Flamingo’s “terribly, terribly sad” death: the very real harms of dyeing animals.

“Flamingo became a bit of a martyr for a greater cause,” she added. “It went viral and got people talking about what a cruel thing it is to dye a poor animal without any regard for its life and the consequences of those actions.

“At the end of the day, that’s what is important.”