Nikki Haley has laughed off being nicknamed “bird brain” by Donald Trump as she continues to make ground in the polls.

The insults, the former South Carolina governor said, were evidence that her rivals were panicking.

“Look, all these guys know that we’re surging in the polls so they’re all starting to hit,” Haley told Fox News.

“The nickname, [Trump’s] losing it, it’s not even a funny nickname. I don’t even think it was that great,” she added.

“But you look at everything else he says, he knows how strong I was when it came to China. I was actually tougher on China than he was.”

As Ms Haley emerged as a potential major challenger to Mr Trump, the former president deemed she was a sufficient threat to accord her the dubious distinction of an insulting nickname.

Not only did he give his former UN ambassador the soubriquet “bird brain”, but a member of his staff left a birdcage – and feed – outside her hotel room.

While the polls still give Mr Trump a commanding lead in the race for the Republican nomination, Ms Haley is threatening to eclipse Florida governor, Ron DeSantis, as the most likely alternative.

On Thursday, they were running neck and neck, with Mr DeSantis holding a narrow two-point lead. Ms Haley is gaining ground or above him in polls in the key early primary states, Iowa, New Hampshire and South Carolina.

And a raft of polls suggest that Ms Haley would defeat Joe Biden in a presidential election. Fox News gives her an 11-point lead and CNN has her six points ahead.

Her strong performance in candidates’ debates has not gone unnoticed, including her savage takedown of early insurgent Vivek Ramaswamy.

More significantly, Ms Haley is winning the support of major corporate donors, whose backing is vital in meeting the astronomic cost of running a presidential debate.

In late October, Ms Haley impressed Jamie Dimon, the chief executive of JPMorgan Chase, in a phone call.

And last week, Charles Koch, arguably the most influential conservative donor, publicly threw his weight behind Ms Haley.

Emily Seidel, senior adviser to AFP Action, the Koch-backed political network, was fulsome in her praise for Ms Haley in a memo.

“It’s now time to help rally those voters behind a candidate who can win the primary and win the general election. That candidate is Nikki Haley,” she wrote.

Kenneth Langone, the billionaire co-founder of the DIY chain Home Depot, has already donated to her campaign.

“I’m a long way from making my mind up – something could change – but I’m very impressed with her,” he told the New York Times.

“I think she’s a viable candidate. I would certainly like her over Trump.”

Speaking to the same paper Eric Levine, a Republican fundraiser, said that some corporate big hitters believe that Ms Haley’s rise in the polls shows that Donald Trump could be stopped.

Mr DeSantis, whose campaign disarray was laid bare by the abrupt departure of his political action committee’s chief executive after only nine days, has turned his fire on Ms Haley.

Last week, he campaigned in South Carolina and dismissed her record as governor in the state.

Ms Haley was unimpressed.

“I think he went after my record as governor because he’s losing. I mean, who else can spend $100 million (£78.8m) and drop half in the polls?

“My record as governor is clear. I took a state that had 11 per cent unemployment, we dropped it down to 4 per cent. We were known as the ‘Beast of the Southeast’ because we created so many jobs and brought so many companies in.”