Wild Island

Possums are among Tasmania’s most familiar native mammals, yet finding a suitable place to shelter is becoming increasingly difficult. As old hollow-bearing trees are lost through development, land clearing and natural decline, many possums are forced to seek alternative shelter in roofs, sheds and other structures.

Nest boxes can help provide an alternative. While they cannot replace the ecological value of natural tree hollows, a well-designed nest box can offer a safe place for possums to rest, shelter and raise their young.

Whether you are looking to support local wildlife, reduce the likelihood of possums taking up residence in your roof, or simply create more habitat in your backyard, this guide will help you choose, build and install a possum nest box suitable for Tasmania. If you are currently sharing your home or garden with possums, our guide on how to coexist with possums provides additional practical advice.

Why Possums Need Nest Boxes

Many native animals rely on tree hollows for shelter, nesting and protection from predators. The problem is that hollows can take decades, and often centuries, to form. Once a hollow-bearing tree is removed, it may be many generations before a replacement becomes available.

For possums, the loss of natural shelter can create significant challenges. Brushtail possums in particular are known to take advantage of roofs, sheds and other structures when suitable hollows are unavailable. Ringtail possums often build nests known as dreys among dense vegetation, but they may also utilise nest boxes in some situations.

Providing a nest box can help supplement natural habitat and give wildlife additional shelter options within their existing home range.

Which Possums Use Nest Boxes?

Brushtail Possums

Brushtail possums are the species most likely to use an artificial nest box. In the wild they commonly shelter in tree hollows during the day and emerge at night to forage. A suitably designed nest box can provide an alternative shelter site where natural hollows are limited.

Ringtail Possums

Ringtail possums are generally less reliant on hollows and often construct spherical nests, known as dreys, using leaves and twigs. However, they may still utilise nest boxes, particularly in areas where vegetation is limited or suitable shelter sites are scarce.

Choosing the Right Nest Box

Not all nest boxes are created equal. A poorly designed box can become excessively hot, collect water, or fail to provide adequate protection from the weather. When selecting or building a nest box, look for the following features:

• Untreated exterior-grade timber.
• A weatherproof roof with an overhang.
• Drainage holes in the base.
• Ventilation near the roofline.
• Internal climbing grooves below the entrance.
• Secure mounting points.
• An entrance hole appropriate for the target species.

Avoid using treated pine or chemically treated timber, as these products may contain chemicals that are unsuitable for wildlife.

How to Build a Possum Nest Box

The plans above provide a simple, practical design suitable for brushtail possums and potentially ringtail possums. The design incorporates drainage, ventilation, a sloping roof for weather protection and a high entrance position to help create a dark and secure internal chamber.

When building a nest box, take care to ensure all joints are secure and that no sharp edges remain. Galvanised screws generally provide greater durability than nails and make future maintenance easier.

If possible, construct the box using untreated exterior-grade plywood or other durable untreated timber products designed for outdoor use.

Installing a Possum Nest Box

Correct placement is just as important as the design of the box itself.

Nest boxes should ideally be mounted between four and five metres above the ground on a mature tree. Where possible, choose a location that receives some morning sun while avoiding prolonged exposure to harsh afternoon sun.

The entrance should remain clear of obstructions and the box should be mounted securely to prevent excessive movement during strong winds.

It is important to remember that wildlife may take time to discover a new nest box. Some boxes are occupied within weeks, while others may remain vacant for months before being adopted.

Common Mistakes

• Using Treated Timber – Chemically treated timber can expose wildlife to substances that may be harmful over time. Always use untreated timber when constructing nest boxes.
• Installing the Box Too Low – Low-mounted boxes may be more accessible to predators and can be more susceptible to disturbance.
• Placing the Box in Full Sun – Nest boxes can become extremely hot during summer. Positioning the box where it receives shade during the hottest part of the day can help prevent overheating.
• Checking Too Often – Repeatedly opening or inspecting a nest box can disturb wildlife and may discourage animals from using it.
• Expecting Immediate Occupancy – Wildlife operates on its own timetable. A new nest box may take time to be discovered and accepted.

Monitoring and Maintenance

Nest boxes should be inspected periodically to ensure they remain safe and secure. Check mounting points, hinges and roof integrity, particularly after severe weather.

Avoid unnecessary disturbance if the box is occupied. In most situations, a brief annual inspection is sufficient to identify maintenance issues.

If wasps or other unwanted occupants establish themselves inside the box, appropriate management may be required before the box can be returned to service.

Sharing Our Backyards with Wildlife

A nest box may seem like a small addition to a garden or property, but it can provide valuable shelter for wildlife where natural hollows are limited. While artificial nest boxes cannot replace mature hollow-bearing trees, they can help bridge the gap and provide important habitat opportunities for native animals.

By installing a well-designed nest box and protecting existing habitat wherever possible, we can help create safer spaces for Tasmania’s wildlife and encourage greater coexistence between people and the animals that share our environment.

Building a nest box is just one way to support local wildlife. If possums are already visiting your property, our guide to coexisting with possums offers additional practical advice on sharing your home and garden with Tasmania’s native possums.