Mary Allen
What material is the ideal nesting box made of? How big does the entrance hole have to be – and where is the best place to hang it?
There is a housing shortage in many large cities, and not just for people. Our native wild birds are also increasingly having problems finding a suitable nesting site. The parks have been tidied up, old hollowed-out trees are increasingly disappearing. Even buildings with smooth facades make it almost impossible for Fink and Star to build nests. Bird boxes and nesting aids are therefore gratefully accepted by them.
The Right Time
In autumn, or at the latest at the beginning of March, you should have nesting boxes up, because then the last garden birds look for suitable roosts in which to raise their young. If you want to attach several boxes, you should ensure that there is enough space between them.
The Right Place
The nest boxes should be well protected from wind and weather. Orientation to the southeast or east is ideal. The north side is too cool, the west is the weather side and the south side can heat up the house too much. Suitable places are house or shed walls or trees – but only rustproof aluminum nails that do not damage the tree should be hammered in here. Free-hanging boxes that are far from branches, among other things, also offer a high level of security against nest robbers.
The Right Material
Plastic and metal boxes cool at night, while the heat builds up inside on warm days. Natural materials such as wood concrete or wood are suitable, the best long-lasting varieties such as oak, beech, Robinia, or larch are suitable. The inside of the wood remains untreated; outside, protection with solvent-free, water-based paints and linseed oil can be applied. Terracotta is also suitable building material.
The Right Design
The roof of the nest box should protrude so that rain cannot penetrate through the approach hole. The overhang must be neither too narrow nor too short so that predators such as cats or squirrels cannot sit on the roof and reach with their paws into the entrance hole. Unfortunately, stakes in front of the entry hole also give nest robbers the opportunity to hold on and reach into the hole.
The Right Entrance Hole
In fact, our wild birds have different demands on their breeding grounds, also with regard to the size of the entry hole. In large gardens, it is, therefore, a good idea to hang boxes with holes of different sizes. Boxes for blue tits should have a small entrance hole 28 millimeters in diameter, great tits need a 32-millimeter hole. For the nuthatch, 35 to 38 millimeters are suitable. The common redstart, for example, likes semi-dens for birds.
Proper Cleaning
The nest boxes can be cleaned in autumn. Nests are removed and the box is thoroughly brushed out. Please do not use any harsh cleaning agents.
By the way: Freshly emptied and cleaned nest boxes should be hung up again. In winter they offer shelter to other animals such as dormice, dormouse, bats, and some insects.