This website is a donation of my time, to make more accessible information about a way that people like you and me can improve habitat for wildlife across Australia, by installing nest boxes.
I have created a companion Facebook group, NestBoxTales for anyone to share stories and learn from other’s experiences, about nest boxes and tree hollow using native wildlife across Australia.
Over 300 of our native species in Australia use tree hollows. Of these, 114 or 15% of our native bird species use tree hollows, the majority for nesting purposes. Some bird species, including Masked Owls, Sooty Owls, Australian Owlet-Nightjars and White-Throated Treecreepers also roost in tree hollows year-round.
Native mammals are also heavily dependent on tree hollows, for sleeping during the day or to raise offspring. Of Australian native mammals, 83 species or 31% use tree hollows. These include bats, possums, gliders, and ground-dwelling mammals that climb such as quolls, native rats, dunnarts, phascogales, cuscus, numbats and antechinus.
Numerous reptile (79 species, 10%) and amphibian species (27 species, 13%) also use tree hollows.
My focus for this website however is on native bird and mammal species that use tree hollows.
Different species have their own hollow specifications, and will not for example make nests in hollows they consider to be unstuitable. Hollows generally need to be within reach on foot or by wing, of food or water sources to be of use. Many animals will also only choose hollows that are sufficiently small to prevent a predator or more dominant tree hollow competitor from entering.
Generally only mature or dead trees have had sufficient time to develop hollows that are most valuable for wildlife. Younger trees may have small hollows suitable for small animals such as reptiles, amphibians, tiny birds and the smallest of the possum species. However only very old or dead trees provide hollows large enough for big species such as Black Cockatoos and Brushtail Possums.
Natural forces such as wind, heat, fire, lightning and wood-eating organisms such as fungi and insects help create tree hollows. Some wildlife, like Galahs will spend months to years excavating a selected spot on a tree to make their own hollow.
There really is no substitute to old growth vegetation with wizened old trees often with numerous hollows per tree, or solitary hollow-bearing mature or dead trees, as vital habitat for native species that will only nest or sleep in tree hollows. Offsetting the clearing of old growth forests, and remnant patches of hollow-bearing mature trees, with tree plantings and the installation of a few nest boxes (that survive a decade or two at best) is no substitute for the loss of vital hollows for breeding and for shelter.
However doing something is certainly better than nothing from an individual person perspective. There is much regeneration of native vegetation across Australia, and also large areas of native vegetation where historic logging resulted in the removal of all large, hollow-bearing trees.
Installing nest boxes where there are few natural hollows remaining certainly provides significant benefits for local wildlife, and can increase the carrying capacity (total number of all different species of native animals able to live in that habitat) of the local ecosystems. If there is sufficient food, and good habitat otherwise, but no natural tree hollow for nesting or shelter, a provided nest box can enable breeding to occur. However there are many tricks to encourage nest box utilisation by a target species and to protect against predators and competitors.
I have created this website to provide easier access to all the wonderful resources about nest boxes available on the internet, by Government departments, researchers, and not for profit organisations. Also to share my experiences, with more than 30 nest boxes now installed on our regenerating woodland property, of successes, failures, experiments and learnings.
Check out the following two pages for more information on bird and mammal species that utilise hollows in Australia:
References: Tree Hollows and Wildlife Conservation in Australia (P. Gibbons, D. Lindenmayer, 2002).