Bill de Blasio was mercilessly booed as the “worst mayor ever” and called “Big Bird” as he walked in Monday’s annual Columbus Day Parade.

“Why is he even here?” retired nurse and Navy veteran Carole Romeo asked as Hizzoner marched by. “He wanted to take down the Columbus statue, he won’t put up the Cabrini statue, he should be ashamed to be an Italian American.”

“Worst mayor ever!” screeched Upper East Sider Karen Anderson as be Blasio passed her perch.

Hizzoner ignored the haters, gripping an Italian flag as he marched the entire parade route to the chorus of boos.

He occasionally stopped to take selfies, approaching only friendly-looking groups.

Parade-goer Dan Manning bellowed “Big Bird” and called the pol a “laughingstock” as he walked by the 45-year-old’s spot on 46th Street.

“You’re not a president, you’re mayor!” Calvin Hunt screamed in de Blasio’s direction as he marched by 56th Street, referencing the pol’s failed 2020 presidential candidacy.

The Harlem resident told The Post he thinks NYPD officers deserve a raise, and then warmly accepted a handshake from a uniformed counter-terrorism officer who approached Hunt after hearing the comment.

De Blasio declined to take questions from reporters, though he did stop to speak privately with Cardinal Timothy Dolan outside St. Patrick’s Cathedral.

Dolan said the two spoke about Mother Cabrini, and the controversial decision by first lady Chirlane McCray to not include the saint in her “She Built NYC” statue initiative.

“This isn’t about the past, this is about the present and the future, let’s do it,” said the cardinal. “The mayor never dodges issues, he always likes to talk about stuff.”

Responding to Gov. Andrew Cuomo’s announcement that he planned to devote state funds to erect a statue of the beloved Italian American, Dolan said, “God brings good out of evil.”

“That’s what’s happening, Mother Cabrini is getting her credit,” he said.