Flora for Fauna Information Sheets:
Nest boxes for native birds and animals
Information courtesy of: Melbourne Zoo Education
Hollows are homes
Many native bird and mammal species rely on hollows in trees for shelter and for breeding. These hollows are formed when the centres of tree limbs rot away due to fungal or termite action.
Hollows take many years to form and so are only present in aged trees (at least 60 years old).
It has been common practice to remove old trees from urban parks for aesthetic and safety reasons, reducing the nesting opportunities of native birds. These birds include Eastern Rosellas, Crimson Rosellas, Laughing Kooaburras, Galahs and rainbow Lorikeets. Mammals that use hollows include Brushtail and Ringtail Possums, as well as Sugar and Feathertail Gliders.
Materials for Building a Nest Box
Timber is best because of its insulating properties. Ordinary Building (O.B.) or Pressure Treated Pine is suitable. Marine Ply is waterproof and durable. Chemically treated pine is TOXIC and chipboard tends to warp when wet. Galvanised /nickel plated screws should be used to join all parts. The nest box must be weather-proofed using a lacquer or creosite, the inside of the box should not be painted. A couple of handfuls of woodshavings or shredded bark should cover the floor.
Ideally, the lid should be hinged and slope down from the back to the front of the box. The lid should overhang the front and sides of the box by at least 25 mm.
Three small (less than 10mm) drainage holes should be drilled in the floor towards the front of the box. Ensure the box is wind and rainproof.
Roughen the roof and inside walls with coarse sand paper or notch with a circular saw before construction: this will enable the young to climb out.
Placement of Nest Boxes
- Different species prefer nest boxes at different heights.
- Nest boxes should be placed where people , cats, foxes or dogs will not disturb them.
- Nest boxes should be sheltered from the prevailing wind and the hot sun.
- Some birds (kookaburras) prefer the nest box to be horizontal.
Attachment of the nest box
Nest boxes can be attached in various ways. Make sure that they are firmly positioned and stable, with a slight forward lean to assist the young to exit and help drainage.
Place a strong piece of wire through an old garden hose and hange from a fork in a tree so that the nest box rests against the trunk. Do not tighten the wire around the tree as this will damage the tree.
Fix a mounting strip to blocks attached to the back of the box. Use 100mm galvanised nails to nail the box to the tree.
Maintenance of the nest box
Avoid disturbing the nest box once it is installed. It may take some time for birds or mammals to ‘accept’ it and take up residence. Introduced birds such as Sparrows, Starlings and Indian Mynahs may nest in the box, and may even take over the nest box from native birds. The nesting materials of these introduced species should be removed as their presence in Melbourne has reduced the availability of nesting sites for native species.
- The Nest Box Book,
by Jim Grant, published by the Gould League. Includes plans and dimensions for nestboxes.
- Contact your local nursery or council for information on where to buy ready-made nest boxes.