If you want to do something good for the songbirds in the garden or on the balcony, now is the best opportunity to do so. For example by adding new nesting boxes. In an expert interview with test.de, Heinz Kowalski from the Nature and Biodiversity Conservation Union of Germany (Nabu) explains what to look out for when doing so. His advice: the best box is of little use if the garden is not also designed to be bird-friendly.
Nesting boxes provide replacement habitat
Why Nabu recommends hanging nesting boxes around the house or in the garden?
Kowalski: There are two reasons. On the one hand, there is often a lack of natural caves. The woodpecker, for example, might hammer into old trees and dead wood, but this is becoming increasingly rare in gardens and the environment. The nesting boxes provide a substitute habitat here. The other reason is that nesting boxes in the garden allow beautiful nature observations. Many bird species, from the red-tail to the swift, like to be close to people. And by the way, it is not only caves that are missing, but also niches. Sparrows, for example, like to nest behind gutters or in spaces between sheds. Wild gardens with old sheds are also becoming increasingly rare.
Ready to move in during spring
When is the best time to install new nesting boxes??
Early spring is the optimal time for nesting. But basically there is no month in which you should not do it. Birds not only breed in nest boxes, but also like to sleep in them. Especially on cold winter nights, they like to huddle together there.
Should old nesting boxes be cleaned – and if so, is now a good time to do it??
Old nesting boxes should be cleaned in autumn or early winter. In February it is still useful, but you have to hurry. The boxes should be clean in March at the latest. When the breeding season really starts, depends also very much on the weather.
© mauritius images / Zen Shui / Odilon Dimier
Why some boxes remain empty
Why is it that a nesting box is not occupied??
There are many reasons. It can lie once at the competition, because in Nach-bargarten are hung up also Nist-boxes, there the offer is sometimes large. Maybe there are too few birds in the area. Since the eighties, the bird population in Europe has decreased by 450 million birds. Besides, it is not enough to provide only a nesting opportunity for the birds: Whether birds move into the nesting boxes also depends on the garden and the surroundings. If there is only golf lawn or even stone fill on plastic foil, it looks bad. There the birds do not find enough food.
It can also be that the nesting box was hung unfavorably?
Yes. The worst mistakes are when the box is placed in full sun, when it can rain or when cats and other bird enemies can get to it too easily.
Should the nesting box be moved if no one moves in??
If again-holt no bird moves in, the disappointment is large. Then a new location should be tried out.
Protect young birds
What do you recommend to protect the birds in the boxes from cats??
The nesting box should be hung up in such a way that cats cannot get at it. It is best not to nail it to the trunk of the tree, but to hang it on the branch with a wire. The birds do not mind that the box is rocking and the cats find it difficult to get to it. Otherwise, there are also special cat defense belts for the trees, so that they can not even climb up.
Does an approach bar on the box help the birds??
No, many people make the mistake of placing a pole in front of the entrance hole of the nesting box. This makes it easier for nest predators such as jays or magpies to land there and grab the young birds from the hole.
Where should the nesting boxes be hung??
It is best to hang the box in the shade, especially not in the blazing midday sun. The opening should face east, because the rain usually comes from the west. It also helps if the nesting box is a little tilted forward and has a canopy, so that the rain can not run in. Wetness is very dangerous for the young birds.
Independent. Objective. Incorruptible.
Also on the balcony
Which height is suitable?
Even if you are naturally curious, the nesting box should not be hung so that you can look directly into it. It should hang three meters high.
Are nesting boxes even suitable for balconies??
Yes. You can also hang them on the balcony. The birds tend anyway rather to move into higher boxes. A balcony with flower boxes would be thoroughly suitable as a location in this respect. When the birds realize that there is enough food nearby, they often like to move in there. Many birds like the blue tit or the red tail can get used to people on the balcony. Once they have learned that there is no danger, they will feed their young even if someone is sitting relatively close to them.
For each bird the optimal home
Which nesting boxes do you recommend for gardens??
In larger gardens you can experiment and create different offers, for example with the usual tit and starling box or half-caves for the garden red-tail. If the environment is right, an owl box can be hung in larger gardens. There should be a park or a forest area nearby, where the owls can hunt for mice.
How large should the entrance holes be?
As for the tit boxes, you can vary with different hole sizes. A box with a small entrance hole with a diameter of 28 millimeters is suitable for the blue tit. The great tit is larger and needs a 32-millimeter hole. For the nuthatch, 35 to 38 millimeters is suitable.
What materials should the nesting box be made of??
The self-construction of a box is very inexpensive and it is also fun to tinker with it together with children. For example, untreated spruce is well suited for this purpose. Even simple wooden boxes often last for many years. Longer-lived are wooden-concrete caves, which are available in the trade. A selection of tested nesting boxes is also available on the Nabu website, for example.
Practical tips from a professional
What do you advise against?
Some nesting boxes, which can be found for example in hardware stores, are much too small. The inner surface should be 12 x 12 centimeters or more – otherwise there is not enough space for the clutch of eggs. In addition, the wood should not be painted with wood preservatives. Smoothly painted surfaces are also unfavorable. Bird lovers should keep in mind that the birds want to find a foothold on the box during their approach and that the offspring will later have to climb up the inner wall to the exit hole. Too smooth surfaces on the inside and outside are in any case a hindrance.
What to look for when cleaning the box?
When scraping out the box, you should wear gloves and cover your forearms – because of the mites and other parasites that hide in the old nest.
Is there any other advice?
A big danger is that it becomes too humid in the nest. As a simple preventive measure I recommend drilling holes in the box from below. Then the water can run off and the holes also provide ventilation. There are still more Tipps to the building for example with the Nabu.
It depends on the environment
How to make your garden bird-friendly?
There are a lot of possibilities. You can grow seed-bearing herbs, create colorful meadows and tall perennials. Beech hedges and dense shrubs provide well protected hiding places for the birds. In general, native species should be grown. Plants from the Mediterranean make little sense. Pesticides and weedkillers should be avoided in the garden. Herbs and seeds attract many birds, but also insects, which are then in turn eaten by the birds. If something is missing in this ecosystem chain of soil-herbs-insects-birds, the birds end up with too little food.