If you think it's tough to break into the housing market in Melbourne, spare a thought for the state's Major Mitchell Cockatoos.
The birds, listed as threatened in Victoria, have such particular tastes in housing that government biodiversity officers have had to undertake a renovation rescue to bring old tree hollows up to scratch.
The picky birds only like hollows in trees that are more than 170 years old. The slender cypress pine trees the birds prefer also need to have cavities a certain depth – 60 centimetres is ideal.
But bushfire in the Mallee in February 2014 destroyed much of the birds' habitat, along with 93 per cent of the known cavity-bearing trees.
To address the housing shortage in the Pine Plains area of the Wyperfeld National Park, south of Mildura, staff from the Department of Environment, Land, Water and Planning decided to trial building artificial hollows in the native pines.
Twenty-five cavities were created between April and May 2014, ahead of the breeding season.
"When we finished doing one of the cavities, a pair of Majors came up and started inspecting the hollow," said senior biodiversity officer Victor Hurley. "Normally they are very shy, so I was amazed to see them go and check it out straight away."
Chainsaws were used to make the hollows, with a wood-carving tool used to smooth out the rough bits. An aromatic bed of pine wood chips was then scattered on the floor of the hollow for nesting.
Dr Hurley said the oils in the soft timber released a scent similar to sandalwood.
"Those aromatic oils deter termites and mites, so it's like a natural insecticide that's sweet-smelling," Dr Hurley said. "It's also like aromatherapy for cockatoos. They really seem to like the fresh chips."
A nest chamber 20 centimetres in diameter will provide enough room for mum, dad and the chicks – that is until the chicks grow and if all four siblings survive, the parents can find themselves temporarily pushed out.
Biodiversity officers have also had to evict galahs from nesting boxes installed for the cockatoos at the national park, which is home to about 34 breeding pairs and considered a stronghold for the species.
However the plastic nest boxes, which don't provide the birds with any thermal protection, are less than ideal.
Temperatures inside the boxes mirror the outside temperatures which can reach the mid-40s in spring and summer.
Meanwhile the artificial hollows built in live trees have natural insulation, which means the temperature in the hollow doesn't fluctuate as much between seasons or the time of day. Dr Hurley said to help with insulation, the artificial hollows needed cavity walls to be a minimum of 10 centimetres thick.
The cavities would be monitored over the coming four years to establish their uptake by the cockatoos but Dr Hurley said early signs were good.
"We weren't sure, if we pretended we were woodpeckers, if the birds would fall for it. But they did and as a proof of concept it's been a success."
