Dying and decaying large limbs and old trees are homes for wildlife and a source of food for insects, which in turn feed other species. Although dead trees and logs may not always be aesthetically pleasing, to Taronga Western Plains Zoo Keeper Mark O’Riordan, they are homes, shelter, nesting places and food for our precious wildlife. With time and education Mark hopes this view will be shared with a greater audience.

By Mark O’Riordan, Taronga Western Plains Zoo Keeper

Tree hollow augmentation

Last week, Taronga Western Plains Zoo contracted two arborists from Oliver Shoemark Tree Services of Bathurst to create six hollow augmentations in the limbs of trees in the Zoo’s 110-hectare Sanctuary. The Sanctuary is a predator free habitat, with a 4.4km newly refurbished predator proof fence, that will soon house Greater Bilbies.

The professional arborists trained some of the Zoo’s Horticulture team members in creating hollows. The team were shown various techniques which will enable them to create a variety of hollow types to attract different species, such as medium sized parrots, Micro-bats and possums. Down the track, we will create hollows ourselves to protect and attract wildlife to the Sanctuary and inner zoo grounds.

Why create hollows?

Australia has over 300 species of native animals that depend on natural hollows for nesting, raising young and housing. An estimated 15% of Australian vertebrate species also use natural tree hollows, some of which can take up to 300 years to form naturally!

Unfortunately many vertebrate species, including threatened species, are in decline because certain land use practices, timber production and chopping down dead trees for fire wood is causing a decline in hollows. Creating hollows utilising the hollow augmentation technique allows us to create a solution to habitat loss in the medium to long term, while revegetation plantings mature and begin to generate hollows naturally.

The hollow augmentation process

In branch stubs – alive or dead – hollow cavities can be artificially created in several ways. One technique involves removing a face plate from the end of the stub, then boring downwards into the end of the limb, before drilling an entrance hole and re-attaching the face plate. Configurations and dimensions can be tailored to attract specific animals.

What you can do to help

Keep old trees standing (dead or alive), and help the natural hollow process by cutting off ‘widow makers’ that don’t have hollows in them already but leaving a few meters of the safe branch stump. Simple pruning techniques and other methods to deliberately enhance the spread of decay can also be beneficial.