Sulphur-crested cockatoos are a familiar, squawking, presence across much of Australia and Melanesia.

But according to a genetic study, they are actually 2 separate species.

And while one of those species is so abundant it’s winning the war against wheelie bins, the other could be in deep danger.

The study, published in Molecular Biology and Evolution, finds that a type of cockatoo which inhabits much of New Guinea – the Triton cockatoo – is a distinct species from sulphur-crested cockatoos.

This means that re-introducing Australian birds to places in New Guinea, where Triton cockatoos are struggling, could do more harm than good.

“Introducing the wrong species in the wrong place could jeopardise their long-term survival in the wild through hybridisation or competition between the Triton cockatoo and the sulphur-crested cockatoo, potentially even disrupting ecosystems in the long term,” says lead researcher Dr Arthur Sands, an ecologist at the University of Hong Kong.

“The sulphur-crested cockatoo, Cacatua galerita, has been thought traditionally to have several subspecies,” explains study co-author Dr Leo Joseph, director of the Australian National Wildlife Collection (ANWC) at the CSIRO.

“There’s some Australian subspecies, and most of the New Guinean populations have been considered to be a subspecies called Triton: Cacatua galerita triton.”

The researchers examined the genomes of cockatoo species from across their range. The genomes came from skin and other museum samples, many of which were stored at the AWNC’s archives.

“The big result, was that the sulphur-crested cockatoo did not hang together as one thing,” Joseph tells Cosmos.

Instead, the Triton subspecies is really an entirely separate species of cockatoo.

The researchers have proposed re-naming the Triton species to Cacatua triton.

Not all New Guinean cockatoos are of the Triton variety.

“Directly across from Cape York Peninsula is a tiny piece of New Guinea called the Trans-Fly, after the Fly River, which is like the Amazon – it’s a huge river,” says Joseph.

“A lot of predominantly Northern Australian species have a little toehold distribution in the Trans-Fly.”

The cockatoo samples taken from the Trans-Fly were found to still be Cacatua galerita – the original sulphur-crested cockatoo.

“I thought every time we studied northern Australian species, we were missing that little New Guinea population. So we we’ve invested effort here at the ANWC, in going to the Trans-Fly and a few other places in New Guinea where you get eucalypts,” says Joseph.

Despite its abundance and popularity, the researchers say there’s been little work done into studying sulphur-crested cockatoo genomes.

“The genome has all this other information about the biology of the animals. In a way, it’s a record of how they’ve survived climatic change,” says Joseph.

In their paper, the researchers call for a better genetic understanding of Triton cockatoos, so their conservation and protection can be better managed.

“Sampling across more of New Guinea, and ideally including type material from museums, would be ideal,” they write.