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Why put up a nesting box?
You can buy nesting boxes in specialized stores, hardware stores and online. There you will find suitable nesting boxes for many species of birds. But of course, you can also build your own. Take out a saw, screwdriver and hammer for a creative activity that you can even get your children involved in.
At the same time, you will also be helping native birds, because nowadays, many of them are no longer able to find adequate nesting sites. This is partly because old and rotten trees are often cut down to eliminate hazards. But it is in these rotten trees that many birds like to build their nests. Artificial tree cavities in the form of nesting boxes are therefore useful for many bird species and represent a small contribution toward bird protection.
Nesting boxes: points to note
Nesting boxes must be dry and dark inside and placed so that natural enemies of birds such as birds of prey, cats and squirrels can’t reach them. It’s also important to make sure that there are no larger overhanging branches in the immediate vicinity of the box.
Position the nesting box in your garden so that it is easily visible and accessible to birds. It should also be protected from wind and blazing sun. Ideally, it should face east or southeast. You should keep in mind that young birds need adequate rest.
It’s also possible to install two or more nesting boxes in the same garden. However, make sure that they are far enough apart so that the breeding animals can find enough food for themselves and their chicks. Birds such as tits have territory covering between 1,000 and 1,500 square meters, for example.
If you want to witness the busy comings and goings around the nesting box, it’s a good idea to mount it on a pole. Make sure that the pole is 1.50 to 1.80 meters high and that it has a smooth surface. This will prevent other animals, such as squirrels, from climbing up it. If you want to make it easier for domestic birds to feed, you should also set up a birdhouse.
Cleaning nesting boxes properly
In the late summer or fall, you should clean the nesting box so that it’s ready for the future guests. Even if there were no birds living in the nesting box during the year, you still need to clean it. Dormice or butterflies may have made themselves at home inside beforehand.
When cleaning, wear gloves, as there may be fleas, mites or flies inside. Remove the old nest and thoroughly brush out the box. You don’t need to use water or cleaning agents.
Different types of nesting box
Depending on the bird species, there are different sorts of suitable nesting boxes designed to meet the needs of birds. We present the most common types of boxes below.
Hole-breeder nesting box
The best-known nesting aid is a box for hole-breeding birds. It is usually small birds such as the tit, sparrow, wren and wryneck that find a home in it. This type of closed box has an entrance hole in the front side. The diameter of this entrance determines which bird species will be able to get through. The necessary dimensions are given later in this post. Nesting boxes for hole breeders are attached to branches, preferably at a height of two to ten meters.
- Blue tit
- Great tit
- Marsh tit
- Common starling
- Pied flycatcher
- Tree sparrow
- House sparrow
Semi-hole breeder box
Birds that don’t build their nests in closed cavities, but in crevices, niches and half-closed recesses require a semi-hole breeder box. The nesting box is closed at the back, and only needs to be half covered at the front. A closed nesting box with several entrance holes can also serve the same purpose. A nesting box for semi-hole breeders and niche breeders should be fixed in a protected place so that the breeding birds are safe from jays or magpies.
Semi-hole breeding birds:
- Pied wagtail
- Common redstart
- Spotted flycatcher
Treecreeper birds build their nests in crevices on trees or behind loose bark. The nesting box should be attached to a deciduous tree if possible. It should be placed at a height of three to four meters and have a side opening. This means that it is within easy reach of the birds.
- Common treecreeper
- Short-toed treecreeper
Sparrows have also become increasingly rare in cities. Most houses today are renovated and well insulated, so sparrows have lost their natural breeding habitat on house facades and roof gables. Sparrows don’t like to breed alone, so a large nesting box with several entrance holes will suit them best.
It is also becoming increasingly difficult for swifts to attach their nests to the exterior walls of buildings. To give them shelter, you should install between three and five boxes under the roof of the house. Swifts prefer nesting sites that they can fly to directly, so you shouldn’t place a swift box below a height of six meters.
Nesting box entrance hole
In addition to the location, the diameter of the entrance hole determines which species can access the nesting box:
- Diameter in mm
- Bird species
- • Blue tit • Coal tit
- • Great tit • Crested tit
- • Tree sparrow • House sparrow • Nuthatch • Pied flycatcher • Common redstart
- • Common starling • Great spotted woodpecker • Wryneck
- • Jackdaw • Stock dove
- • Tawny owl
It’s best to use unplaned wood that’s 20 millimeters thick. The most durable types of wood are oak, robinia and larch. Pine or spruce boards are also good choices for a nesting box. We describe the construction process below, taking the example of a nesting box for the blue tit. This is the material you will need for building a nesting box:
- 2 boards for the side walls
- 1 board for the back wall
- 1 board for the front
- 1 board as a roof
- 1 board as a floor
- 1 old piece of bark to cover the roof
- 18 countersunk screws for screwing the boards together
- 4 short countersunk screws for attaching the bark
- 2 screw hooks for attaching the nesting box
- 2 screw eyelets for attaching it to the tree
When building a nesting box, it’s best to have the following material on your workbench:
- Wood and Forstner drill
- Cordless screwdriver and bits
- Wood rasp and sandpaper
- Stop angle
- Measuring tape
Dimensions of nesting boxes
The Swiss Ornithological Institute in Sempach recommends the following dimensions for nesting boxes (in centimeters, wood thickness of 2 centimeters):
- Bird species
- Side wall
- Back wall
- Entrance hole
- Blue, marsh, crested and coal tit
- Great tit, pied flycatcher, tree sparrow, House sparrow, nuthatch
- Common redstart
- 3,0×4,5 (vertical oval)
- Common starling
- Stock dove
- 7,0×8,5 (oval)
- 35 22×40
- Tawny owl
Cut the components for the nesting box
First, start by cutting the boards. It’s best to use a jigsaw or a small circular hand saw. Clamp the board on a workbench beforehand to prevent it from slipping as you saw. Since the roof will be at a slope, saw the top of the two side pieces so that the front is four centimeters shorter than the back.
Make the entrance hole
To protect young birds from enemies, place the entrance hole at least 17 centimeters from the bottom of the box. When calculating the position, you should also take into account the thickness of the base. It’s best to position the mark for the lower edge of the entrance hole 20 centimeters from the bottom. The most suitable tool to use is a Forstner drill with a diameter of 25 millimeters. Make a circular entrance hole with it. With the help of a wooden rasp, you can then widen the opening to up to 28 millimeters – depending on which feathered friends you are expecting in your nesting box.
Drill drain holes in the base
To prevent moisture from collecting in the nesting box, drill two staggered drainage holes of a diameter of six millimeters in the base.
Put together the nesting box
Now all the components are ready and you can assemble the nesting box. The easiest way to do so is to fix the pieces of the box together using a cordless screwdriver. Use two countersunk screws on each edge. You will need one screw on each side of the front board only, approximately level with the entrance hole. Otherwise you won’t be able to open the front later. Alternatively, you can use nails. Finally, attach the roof of the nesting box to the back wall as well as the side walls – done! Now you can hang the nesting box in a suitable place in your garden.