The sound of chainsaws fills the forest of Bruny Island in Tasmania as a group of 30 arborists cut into white peppermint trees, which provide essential nesting for the endangered swift parrot.
The arborists, from Victoria and Sydney, paid for their own flights and volunteered their time to climb into more than 100 trees and carve holes in them to provide safe nesting for the birds, which are fussy about where they will breed.
Dejan Stojanovic, a conservation biologist who researches the parrots and is dedicated to preserving their environment, struggles to contain his excitement as he speaks over the chainsaws to Guardian Australia on Friday. He hopes the human-made hollows will lead to a breeding season boon for the birds.
“My research has shown that of the naturally available tree hollows in the Tasmanian forest, only 5% are suitable for swift parrots,” he says.
“The parrots are really picky about where they will nest, and the holes must have certain characteristics or the birds won’t use them. The average nest is between 40 and 50cm deep, and the entrance hole in the tree needs to be small, about 5cm in diameter.
“The birds need that small entrance to prevent Tasmanian predators (which typically have fat heads, like sugar gliders) from getting into them.”
Habitat loss owing to logging, illegal firewood cutting and clearing land for farming and housing means that safe and appropriate breeding spaces for the birds are increasingly rare. While numbers are hard to ascertain, Stojanovic says there are only about 2,000 of the parrots left. Habitat loss has accelerated their deaths to sugar gliders, which kill and eat the female parrot while she incubates her eggs, or return over several nights to feast on nestlings.
But Stojanovic’s research team has had an exciting week. In a further attempt to encourage breeding, they launched a crowdfunding campaign through Pozible last year to build sugar glider-proof nest boxes. They raised $73,000 and by the end of the year had placed hundreds of nest boxes throughout the forest.
Last week Stojanovic checked 40 of the boxes and found 11 of them occupied by the parrots. He has climbed up to check inside three of those 11 boxes so far, finding one containing six eggs, another containing four and one with a nest chamber prepared, signalling a parrot was about to lay.
“It was three out of three,” Stojanovic says. “I’ve only ever recorded one natural nest with six eggs in it before, and it’s another sign it will be a great year for the parrots. It’s nice to be able to say to people who donated to our campaign that their money has gone to good use, and it’s such a relief for us.”
A combination of factors are working in the parrots’ favour this year, he says. Their food source, blue gums, are flowering heavily, providing a food bonanza in an area of the island protected from sugar gliders. And, thanks to the efforts of researchers, there are more nesting options available to the birds than ever.
But Stojanovic warns the parrots are nomads which move to different areas of Tasmania according to where blue gums are blooming. Deploying arborists to climb trees and carve out nesting holes each season according to where the birds are, combined with building the nesting boxes, is an expensive and time-intensive endeavour.
“This is a Band-Aid solution and a desperate attempt to buy time for these birds by giving them a reprieve for their habitat loss,” he says. “But what we need to do long term is preserve mature Tasmanian forest.
“When you consider that this is the best year for the birds since 2005 in terms of conditions and food supply, that’s 11 years between drinks.
“It is highly likely that next year the blue gums won’t flower as well as they did this year and they might not for another five years, forcing the birds on to the mainland to breed where there is less habitat and more predators.”
Andrew McKernan, an arborist with Melbourne Tree Care, spent Friday ascending the peppermint trees, which he says had been chosen because they aren’t endangered and are near to the blue gums.
He heard Stojanovic on the ABC’s Radio National program early this year talking about the parrots and their natural habitat being destroyed by illegal firewood cutters. He contacted the ABC and asked to be put in touch with Stojanovic.
“I said, ‘I think we can help him,’” McKernan says.
McKernan and others have been experimenting with carving hollows out of trees to provide nesting for birds and, with the support of the Victorian Tree Industry Organisation, he found other arborists willing to help the swift parrots. Natural hollows take decades to form and are usually only found in mature trees, he adds.
“We’ve been saying that doing this carving works to help the birds, but we have only had anecdotal evidence in the past, so it’s hard to get people on board to support doing it more widely,” he says.
“The good thing about this project is that it will form part of the research project into the parrots so we can get some scientific evidence about the impact of carving these nesting hollows on bird numbers.”
McKernan adds that carving out the holes is a highly specialised technique that requires training, and that each one takes about an hour including the time needed to ascend and descend the tree. “It’s a very different way of handling a chainsaw, and it is a difficult and dangerous way to use a saw if you’re not well-trained,” he says.
McKernan says he is confident the human-carved nests will be used by the birds, adding that he is passionate about conservation.
“One of our fears with what we’re doing is that the logging industry might say, ‘We can cut more trees down if people can just cut more hollows,’” he says.
“But the work we are doing is just a short-term solution. We need to be saving and preserving mature forrest.”
