Large flock of rare swift parrots seen near Port Macquarie

James Bennett has spotted a flock of swift parrots at Lake Cathie. (Supplied: James Bennett)

A flock of about 50 critically endangered swift parrots has been spotted at Lake Cathie, in northern NSW.

The sighting is seen as significant as hardly any swift parrots were seen in NSW during their winter migration from Tasmania last year.

Conservationists are working with the species to boost its numbers, with key threats including habitat loss and predators raiding nests.

Avid birdwatcher, James Bennett, was out looking for a rare bird recently near Port Macquarie when he heard a distinctive call that piqued his excitement.

"For the last month or so, I have been checking areas for swift parrots, which are a winter migrant … some years they miss these spots, but it's always worth checking," he said.

"It was flogging down with rain, and I had the windows down in the car listening for their call … it's a very distinctive call, and when you hear it, you know."

Mr Bennett alerted other birdwatchers and they recorded not just one or two, but a large flock of about 50 birds at Lake Cathie, south of Port Macquarie, on the New South Wales Mid North Coast.

Swift parrots migrate from Tasmania to the mainland during the cooler months. (Supplied: James Bennett)

It is a significant sighting of a species, which conservationists estimate is down to between 750 to 1,500 birds in the wild.

Swift parrots breed in Tasmania during the summer before migrating to the mainland in search of food in the cooler months.

"They really are an incredible looking bird with their bright scarlet coloured face, long pointed tail and very unique call and feeding antics."

James Bennett says he spends much of his time out searching for rare bird species. (Supplied: James Bennett)

BirdLife Australia's regent honeyeater recovery advisor, Mick Roderick, said the sighting was encouraging after last year, when most of the swift parrot population did not migrate further north than Victoria.

He said in addition to the 50 recorded around Lake Cathie, there had been recent reports of swift parrots elsewhere on the Mid North Coast, including 10 at Crescent Head.

Swift parrots migrate north in search of food, this one seen with a large flock at Lake Cathie. (Supplied: James Bennett)

They have also been recorded around Sydney and the NSW Hunter region, and even a couple north of the Queensland border at Brisbane.

"It's really exciting given we barely had any swift parrots in all of NSW last year," he said.

A swift parrot feeding on lerp at Lake Cathie. (Supplied: James Bennett)

Mr Roderick