345 different species of Australian animals need tree hollows – some like cockatoos, many parrots, owls, some smaller birds, kookaburras and ducks only need them in breeding time. Others animals such as goannas, tree snakes, quolls, some antechinus and dunnarts, use them opportunistically. But right now, the nocturnal mammals that rely on hollows daily – possums, gliders, phascogales, different microbats species, need boxes to be strategically placed in suitable habitat which they will hopefully find as they move from the fire ground, or to where they can be released if they have been in care. Providing nest boxes means they can be safer from predators as they seek food nearby and shelter by day. We have lost millions of hollow bearing trees across Australia, so right now nesting boxes are vital to help animals survive.
Just a note – obvious but needs to be said – don’t cut down existing hollows or take hollow logs to make boxes. That’s someone else’s home! These really were saved from the chipper.
I topped some of the hollows with FSC marine ply (but use any recycled hardwood too) and I added some recycled mini tramp springs (attached to the hollow with bolts) to accommodate future tree growth – hose covered fencing wire is used to wrap around the tree. Some drainage holes were also cut into the bottom. Boxes can be pretty heavy so you may need to place them in a tree fork – which also gives animals a ‘cross road’ to come and go from. Make sure that the tree you select has some connectivity above where branches intersect so that animals can move about the treetops -especially arboreal animals such as gliders that are very vulnerable on the ground. Place the box in a sheltered position preferably with a bit of canopy cover so that smaller animals are safer from hungry owls and birds of prey.
Species such as yellow-bellied gliders may use hollows that are 25 metres up a tree. That may be way beyond the feasible reach for the average person. Ideally boxes need to be secured a minimum of 4 metres up – but even higher if you have the capacity. Remember, the purpose of providing nest boxes within this context is about offering instant habitat nearer to food sources – natural hollows in the preferred location are always going to be better! This is not an exact science – and nesting boxes have shown very mixed success rates – but a well considered nesting box may be a good life-saving interim. For experienced chain saw operators, a cut-in is (cavity cut into a live or dead tree) another, often better, alternative to nesting boxes. seethe link below for tips. It is also important that you make sure your pets are not going to scare or harm any native visitors – keep pets inside at night and pop a bell or two on the cat.
A few last tips – make sure you build the box from thick timber. Thin boxes are just ovens in summer and freezers in winter. Use untreated timber on the inside, but you can use painted timber on the outside provided it is not toxic – such as lead based paints. You may also need to add grooves on the inside, and or attach a stick on the outside for grip if the timber is very smooth. Another idea is to add a little piece of timber on the inside of the entrance which blocks the immediate view in, a small mammal can still manoeuvre around it, but it may be enough to block a predator (such as their sharp claw).
What happened to these boxes? These boxes were installed on the south coast of NSW where there are significant glider and eastern pygmy possum populations.
They are being monitored by researchers and wildlife carers who are also providing supplementary feeding until the bush can provide adequate food.
If you want to make some boxes check out the link below for instructions on making traditional boxes or use my pics for tips. You may also like to download the list of Australian species that need tree hollows, and this helpful guide to building nest boxes for wildlife here. For seriously experienced chainsaw operators have a look at this article for advice. For those that want a bit more science behind best nest box practice check out this article. And to learn more about tree hollows and the cool critters that use them read A Hollow is a Home.
If you want to make a few boxes, or share your skills, wildlife rescue centres will be most grateful for any donations. Hope the animals find them. Fingers crossed.