Only 123 adult kakapos (Strigops habroptila) remain in New Zealand.

This year, 37 kakapo chicks have survived so far, making it the most successful breeding season in more than 20 years of conservation efforts, researchers say.

It will be six months until the chicks are added to the head-count of the total kakapo population, Conservation Minister Maggie Barry said in a statement.

New Zealand’s extremely rare kakapos (Strigops habroptila) have received a much-needed boost.

This year, 37 kakapo chicks have survived so far, making it the most successful breeding season in more than 20 years of conservation efforts, researchers say. Previously, 2009 held the record with 33 hatched chicks.

The chick numbers “signal a new era for kākāpō conservation,” Diedre Vercoe, Department of Conservation’s kākāpō operations manager, told the Guardian. “…technological advances are enabling us to look after more kakapo in a non-invasive way, and as the population grows, these tools will be crucial.”

Kakapos — the world’s heaviest parrots — were once abundant throughout New Zealand’s North Island, South Island and Stewart Island. Numbers of these big flightless birds declined drastically when Maoris and then European settlers began hunting them for meat, skin and feathers.

Introduced predators such as dogs, cats, toats, and ferrets also preyed on the naïve kakapos, their eggs and chicks, further reducing the birds’ numbers. Collectors, too, killed numerous kakapos.

In fact, for a while kakapos were thought to be extinct until scientists began re-discovering some small populations in the 1970s. A Kakapo Recovery program established in 1989 now helping these giant birds stage a comeback. Today, there are 123 adult kakapos on protected islands.

Each adult kakapo is being monitored closely and has its own tracking device that tells the scientists when the bird moves, mates, feeds and lays eggs. The device also signals when the mother gets on and off eggs and for how long. All data is sent to the email inboxes of relevant staff at kakapo operations bases via satellite, the Guardian reported.

The critically endangered kakapos do not breed easily. These birds breed only once in two to five years, when there is a good crop of fruits of the rimu tree (Dacrydium cupressinum). This year, the fruits’ supply has been good, scientists say, which is helping the big birds. The breeding season began in October 2015 and the last chick hatched on April 8.

But young kakapos are vulnerable and the coming weeks will be crucial, scientists say. Conservationists will monitor and weigh the chicks regularly until they fledge at around 10 weeks old, according to a statement by the New Zealand government. If the chicks find it difficult to survive in the wild, they will be brought in for hand-rearing, the statement added.

“It will be six months until the chicks are added to the head-count of the total kakapo population,” Conservation Minister Maggie Barry said in the statement.