Several birds, such as Tits, build their nest in a cavity: hollow tree, hole in a building or under a roof, letter box, old water pump, etc... Unfortunately, such cavities are disappearing at an alarming rate as hollow trees are taken down, buildings are impeccably renovated... Even if the environment has sufficient food resources, they no longer offer favourable nesting sites.
(photo Patricia)
(photo Bruno)
To help compensate for this disappearance, the installation of nest boxes suitable for cavity nesting birds is a solution both "simple and effective" to implement in your garden. Ready to hang models exist but it is very satisfying to construct them yourself and to involve ones children and their friends.
All conditions of comfort and safety necessary for the birds to survive must be combined. The nest box must be big enough, with a base of 15 x 16 cm. And a minimum height of 15 cm. Between the entrance hole and the floor of the nest box. It must be waterproof and resistant to bad weather. Avoid nest boxes with walls that are too thin, inadequate mountings or with any splits.
It is necessary to imitate natural conditions as best as possible. The inside is left rough, untreated and not planed down, in order that the birds can leave by clinging on to the surface of the wood. The exterior is a neutral colour, the ideal being to leave it to tone down naturally or to cover it with bark.
Blue tit
Each species has its own requirements. The nest box must be adapted for the bird you wish to attract, e.g. entrance hole for a Blue Tit: 28 mm; Great Tit: 30 mm; but to keep things simple, one can make a hole of 30 mm for both species.
(photo Raymond)
Do not place in full sun or in total shade. The entrance hole should face away from the prevailing wind direction with the nest box tilted slightly foreward to protect the birds from bad weather. It is advisable to face the entrance towards the south-east. The nest box should be hung in a quiet place, on a wall or a tree, out of reach of the inquisitive, two or four footed.
If after 2 or 3 years the nest box remains unoccupied, check that you have followed all this advice and look for another location.
You can hang your nest box from autumn to the beginning of winter as certain species, such as Tits, look for suitable sites very early, and others, like the Wren, will sometimes roost there in winter.
The majority of birds defend their territory against intruders of the same species. It is therefore useless, even harmful, to hang too many nest boxes destined for one species (or species needing the same diameter entrance) in one area. It is also good to vary the models, and to respect minimum distances between two identical nest boxes: 15-20m for the Blue Titi and 40-50m for the Great Tit.
