KEEPING a threatened species alive is a special thrill for ornithologist Bruce Quin.

Last week, 11 helmeted honeyeaters - seven bred in captivity at Healesville Sanctuary and four from Taronga Zoo - were released at Bunyip State Park.

The birds were given a chance to acclimatise to their new surroundings in on-site aviaries before joining only 65 confirmed helmeted honeyeaters in the wild across Victoria.

A Monash University and Zoos Victoria team will track the movements of the birds via radio for the next three months.

Mr Quin, who works for the Department of Sustainability and Environment, will help monitor the released birds.

He said numbers had slightly increased since 1989 when the intensive recovery program, designed revive the species, had begun.

At that time, numbers at the last surviving colony at Yellingbo Nature Conservation Reserve, in Healesville, hovered at about 50.

Mr Quin said without the program, chances are the bird may have been extinct by now. Even with the program, numbers remain fragile.

Since 2001, 140 birds have been released into Bunyip State Park -about 33per cent of the birds survived for more than a year, and 22per cent bred in the wild.

"It is exciting and quite satisfying to see it happen. We're especially happy with the Bunyip State Park population because we created that from zero.

Colonies in Bunyip State Park survived Black Saturday bushfires, with the closest nest just 350 metres away from flames. Regrowth attracted helmeted honeyeaters to the burnt areas just 10 months after the fire.

Mr Quin said part of the challenge to keep the species alive was to protect eggs and nestlings from predators.

He added that birds freed from captivity are "more naive than they should be."

To protect the nests, a plastic mesh trellis is added which shields the nestlings and eggs from hawks, kookaburras and brush-tailed possums.

More problematic are tiger snakes - one evaded the protective perspex ring around a nest via a lead from a camera used to monitor the birds.

Mr Quin said as part of the survival plan, captive-bred baby birds were added to nests and eggs swapped to increase the gene pool. Supplementary food was also provided and the helmeted honeyeater's preferred vegetation propagated.

"To back off from active management is the ultimate aim, but with the population still pretty low, it's quite some time off," Mr Quin said.

"We really need several colonies and several hundred birds or more to be comfortable."