High above the windswept button-grass plains of Melaleuca in Tasmania's south-west, a fluffy chick is tucked away in a nesting box. But this is no ordinary chick.

The little bird is the first captive-bred orange-bellied parrot to have survived its first week in the nest of an adoptive mother in the wild.

It is the sole survivor of a clutch of five chicks flown across Tasmania in a helicopter and placed in the wild parrots' nesting boxes as part of a last ditch effort to save the endangered species (Neophema chrysogaster).

Dr Dejan Stojanovic of the Australian National University said transporting the tiny three-gram fluffy 'jelly bean'-sized babies, aged between one and five days old, was "terrifying" and "gut wrenching".

While cross-fostering techniques have worked in captive-bred orange-bellied parrots, this is the first time the technique has been trialled in the wild in this species.

Sorry, this video has expired Nest-cam of week-old orange-bellied parrot chick Source: Dejan Stojanovic

"We wanted to see whether mums would be able to adopt the kids, and ultimately rear in the bush as truly wild parrots," said Dr Stojanovic, who is leading the trial with Dr Shannon Troy from Tasmania's Department of Primary Industries, Parks, Water and Environment (DPIPWE).

While four of the five chicks died, this one is holding on — at least for now.

"Thankfully we've had a foster nestling survive for a week after being moved, which is a huge milestone, but it's also so fragile that anything could still happen," Dr Stojanovic said.

"This last week has taken us on a very steep learning curve about the way we can intervene to help orange-bellied parrots, but there are no guarantees of survival for our foster nest."

And, with no other opportunities to foster chicks this season, a lot is riding on this one nestling.

Intensive intervention only way to save parrots

Two tiny foster nestlings moments before they were put in a thermoregulated esky and hauled up a tree to meet their new mother. ( Gemma Deavin )

Each year, orange-bellied parrots, which weigh less than a mobile phone, migrate from their wintering grounds on the South Australian and Victorian coast on the Australian mainland to Melaleuca to breed.

But the 2016 migration was the most dismal on record with only 17 wild birds — four females and 13 males — returning.

These low numbers triggered an emergency intervention plan, including this world first cross-fostering attempt; an attempt backed by a crowdfunding campaign.

"With only four wild birds available to breed there's no way orange-bellied parrots can recover without intensive intervention," Dr Stojanovic said.

Elsewhere in the world fostering, brood manipulation and nest rescue intervention examples have been successfully employed in the recovery programs for the echo parakeet (Psittacula eques), Mauritius kestrel (Falco punctatus), black robin (Petroica traversi) and the pink pigeon (Nesoenas mayeri).

Dr Stojanovic said the classic textbook example is the New Zealand robin — a species whose entire modern population is descended from one single female bird.

But the orange-bellied parrot is much more of a challenge to conserve than these other species because its migratory nature exposes it to many threats such as habitat loss across their migratory path, predators and an ocean crossing.

The first days are critical

ANU's Dejan Stojanovic marks one of the five nestlings with a pen so it is identifiable when it goes into the nest ( Supplied: Gemma Deavin )

Orange-bellied parrot facts Orange-bellied parrots are about the size of a large canary and weigh 50-60 grams.

Orange-bellied parrots are about the size of a large canary and weigh 50-60 grams. Each summer, they migrate from the Victorian and South Australian coast to Melaleuca in south-west Tasmania to breed.

Each summer, they migrate from the Victorian and South Australian coast to Melaleuca in south-west Tasmania to breed. There are only about 40 parrots left in the wild.

There are only about 40 parrots left in the wild. Threats to the parrots include loss of salt marsh habitat through fire and clearing; competition from introduced species of seed eating birds such as sparrows and native birds such as the blue-winged parrot; predation from foxes and feral cats.

Threats to the parrots include loss of salt marsh habitat through fire and clearing; competition from introduced species of seed eating birds such as sparrows and native birds such as the blue-winged parrot; predation from foxes and feral cats. The parrots have a very short breeding season. Eggs are laid in early October through to early December, and pairs rarely, if ever, double clutch in one season.

The parrots have a very short breeding season. Eggs are laid in early October through to early December, and pairs rarely, if ever, double clutch in one season. They lay up to five eggs, followed by an incubation period of around 21 days, and chicks fledge at 30 days of age.

As well as supplementing nests with nestlings or eggs from captivity, the emergency intervention involves intensive monitoring of every active nest box in the Melaleuca region, every three days.

The scientists involved in this trial were most nervous about the nestlings' first days in the foster nest.

"Fostering had never been attempted into wild nests so we were anxious to see if the technique worked," Dr Stojanovic said.

"The foster nestlings are so young that if they're not accepted by their foster mums quickly they are extremely vulnerable."

Wildlife handler Jocelyn Hockley said if the foster mother does not take to the newly fostered chick immediately it won't survive more than a couple of hours.

"When they're a couple of days old they're getting fed every two to three hours, and it's important the mother sits on them to maintain the correct temperature," said Ms Hockley, who has worked with captive-bred parrots for 12 years.

Four of the five chicks died in the first week, but the surviving chick appears to be going well, said Dr Stojanovic, who checked the nest last Sunday.

"She — I'm hoping she's a girl — was pink and fat, exactly how I like my baby parrots," he said.

"She was all snuggled up to mum and looked great — with a full belly.

"Mum was actually in the box and you could see her little blue mono-brow (a trademark feature of orange-bellied parrots) all furrowed."

Captive breeding not enough to boost wild flocks

Dr Dejan Stojanovic inspects one of the nesting boxes in the tree canopy 10 metres above the ground ( Supplied: Gemma Deavin )

The foster chicks came from a captive breeding program set up in 1986 by the Orange-Bellied Parrot Recovery Team — a group of government wildlife authorities, conservation groups, captive breeding centres and volunteers — as an insurance population.

"There wouldn't be birds to release as adults to boost the population every November. There wouldn't be birds available for this trial," said DPIPWE wildlife biologist Dr Shannon Troy.

The release of adult birds is primarily around balancing the sex ratio and increasing the potential breeding opportunities.

Results from the past three years of introducing captive-bred adult birds into the wild population show these birds breed successfully, but the survival rates of adult captive-bred birds between seasons is very low.

In contrast, chicks from captive bred birds appear to return at similar rates to young from two wild-born parents, suggesting the birds are better equipped to migrate when reared in wild nests.

Risk from disease

A clutch of four older non-captive bred nestlings at Melaleuca ( Supplied: Gemma Deavin )

Captive-bred birds are also very vulnerable to disease.

An outbreak of disease at the Taroona Wildlife Centre, where the fostered nestlings were sourced, highlighted the urgent need to boost the wild flock, said Dr Stojanovich.

Sixteen adult birds out of a population of 136 at the centre have died since January 1; a higher mortality rate than expected for this period.

All the birds have undergone post-mortem investigation and results have returned positive tests for a deadly bacterium called Pseudomonas aeruginosa in four adult birds and one nestling from Taroona, and one of the cross-fostered nestlings from Melaleuca.

"There are always going to be events that will impact orange-bellied parrot populations, but that's why it's important to have a robust and wild population in adiition to the captive flock spread across multiple institutions so they can support one another and act as backups," Dr Stojanovic said.

"This latest disease outbreak reinforces the need to support the recovery of the wild population and to test the limits of what types of intervention are possible before it is too late."

The disease outbreak also cuts short this season's trial.

The team had hoped to move more foster nestlings into the remaining two available nests, but this will no longer be possible.

"Further cross-fostering plans will be on hold until the disease is brought under control," Dr Stojanovic said.

The next tentative steps

Orange-bellied parrots at a feeder ( Supplied: Henry Cook )

Despite losing four of the five chicks, Dr Stojanovic was still optimistic.

"Even though these deaths are a blow we've learnt more about orange-bellied parrots from these failures in the last three weeks than we could have hoped," he said.

"Next year we'll be in a much stronger position to help boost the wild numbers."

For now they are anxiously watching the progress of the sole surviving foster chick in the hope that it live long enough to leave the nest in another 20 days.

"I will be very excited to watch our little foster nestling growing over the next few weeks — it'll be amazing if we can see it fledge the nest," Dr Stojanovic said.

Dr Troy said seeing the foster nestling feed at the tables will be the first stage in the 'this is working' assessment.

The second stage will be if it survives until the end of the season at Melaleuca.

"The final stage of success will be if the foster nestling migrates north to the southeast of Australia, and then migrate back again for the next breeding season," Dr Troy said.

"If we see the nestling again next breeding season we will be delighted."