Blue Mountains News

Outside a kitchen window in Wentworth Falls two Crimson Rosellas found a hollow. It was small, only about 5 centimetres deep, because the host tree was relatively young. Each morning the birds would visit and try to expand the hollow and make it deeper to accommodate a nest for their young. 

Peter Ridgeway, who works in biodiversity restoration, was moved as he watched from his home. “They kept at it almost every day for nearly two months before finally giving up,” he said. He has since often wondered if they ever found a place to raise their chicks. “It brought home to me how in desperately short supply hollows are, and the impact this has on our wildlife.”

The word ‘hollow’ might suggest an emptiness. However, in the case of trees, it is anything but. Weathered and gnarled, bearing the wounds and scars of its years, an old tree is a sight to behold. Its traumas are character-building, telling stories of survival against the odds. Its traumas are also crucial for the survival of other creatures, who reside deep in the wounds of that mottled wood.

Hollows are the result of injury. While the external part of a tree may continue to grow, injuries allow the entry of fungi, bacteria and wood-chewing insects that cause decay or the hollowing out of the internal wood. They can take hundreds of years to form, so they only occur in very old or dead trees. Only certain tree species form hollows and only specific species of Eucalypts form appropriate hollows that accommodate the needs of particular wildlife.

In Australia, over 300 species of native mammals and birds require hollows for shelter, roosting, and breeding. Each animal has distinct requirements for their ideal accommodation, meaning the greater variety on offer, the better.

The problem is that hollows are in diminishing supply. Historical and ongoing loss of old trees due to clearing, arboriculture works, and bushfires causes ongoing loss of habitat for much of our wildlife.

To raise awareness and provide people with an opportunity to help, the Blue Mountains Conservation Society hosted a nest box event at the Mid Mountains Neighbourhood Centre in Lawson earlier this year.

Peter was invited as a guest speaker. His presentation offered a broad sweep of background information as well as practical advice about the use of nest boxes as supplemental habitat for hollow-dwelling creatures. “Our local wildlife will never thrive unless we take action to increase the hollows available for them,” he said. “The shortage of hollows is a problem created by our modern lifestyles and decisions, but we also have the opportunity to be the solution.”

So, is it as simple as building or buying a nest box and whacking it on the side of a tree? Not quite. While nest boxes may successfully provide supplemental habitat for some creatures, there are some important factors to consider.

Learn more about nest boxes, what types suit which animals and how to install them correctly, along with other ways to help here: https://www.midmtnslocalnews.com/nesting-needs/