But last year, the company that makes the curiously popular ornaments dropped the signature, puzzling Featherstone and ruffling the feathers of flamingo fans.
Some, including the Museum of Bad Art and The Annals of Improbable Research, are calling for a boycott of the new, bare-butted bird.
"They're desecrating this oddly beloved object," said Marc Abrahams, editor of the Cambridge-based annals, which awarded an Ig Nobel - a mock Nobel Prize - to Featherstone in 1996.
Thomas Herzing, author of "The Original Pink Plastic Flamingo: Splendor on the Grass," called the decision "disrespectful" and a "sharp stick in the eye of high art."
The company, Union Products Inc., has refused to explain the change - even to Featherstone, its former president.
Featherstone, 65, a sculptor with a classical art background, modeled the ornament on a bird he saw in National Geographic. He created more than 650 other pieces, penguins and snowmen among them, but none took off like the pink bird. More than 20 million have been sold.
Featherstone's signature was added in 1987 to make it more like a piece of art and harder to copy, Featherstone said.
He retired in 1999 as Union Products president and his signature disappeared soon after.
"There was no bad blood," Featherstone said of his relationship with company managers. "I'm puzzled and disturbed."
By Jay Lindsay © MMII The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed