There are several ways to attract birds to their garden or balcony: feeding them in winter, providing them with water for drinking and bathing, planting favorable plants, not using chemicals, or installing a nest box. Many species need artificial nesting sites because their natural habitats are becoming poorer: dead hedgerows and trees disappear, facades of new buildings are smooth and hermetic, old piles of wood and rocks are eliminated, and Walls are destroyed.
Even if the installation of a nest box does not compensate for this heavy trend, it is a concrete gesture for our winged friends and a source of wonder for adults and children. In this article, we have selected ten important principles or "commandments" to maximize the chances that your birdhouse will be used and appreciated by birds.
Choose The right model
The size of the entry hole allows you to select the hosts you wish to privilege (read the different types of nest boxes):
- For blue Cyanistes Caeruleus, black Parus Ater and Poecile Palustris, the hole will have a diameter of 25 mm.
- For the Great Tit (Parus major), Sparrow (Passer montanus) and Black Flycatcher (Ficedula Hypoleuca), the diameter of the hole will be 28 mm.
- It will reach 32 mm for the House Sparrow (Passer domesticus) and the Nuthatch (Sitta europaea), and 45 mm for the Common Starling (Sturnus vulgaris).
- The shape is also important: if the chickadees, nuthatches or sparrows prefer the traditional nesting boxes, the familiar Red Robin (Erithacus Rubecula) and the Blackbird (Turdus merula) prefer those with a large rectangular opening in the front and middle depths 100 mm).
- The Gray Flycatcher (Muscicapa striata) needs a very shallow (60 mm) nest box in order to monitor the entry hole, while the Crested Troglodyte (Troglodytes troglodytes) is looking for a high nest box (140 mm ).
The interior of the nest should not be too smooth so that the young can grip and easily get out.
There are many types of ready-to-use nest boxes for different species in the market, but you can also build them yourself by associating your children. There are several plans available on the web, and do not forget that there are also nest boxes for bats!
Fix it solidly
It is necessary to tie your nest box to a solid and stable support, thanks to one or to fixings which do not risk to rust or to alter with time (galvanized wire, sheathed electric wire, etc.). If you attach it to a living tree, be careful not to hurt it: do not use nails.
The growth of the tree will not be impeded by placing a piece of wood between the trunk and the wire.
Choose a good material
The nest box must be solid, robust, made with boards at least 15 mm thick. Avoid treated wood (or use non-hazardous products): over time, it will take a duller shade that will help melt it into the environment.
The softest woods can, however, be treated with Sadolin, a product that is not very dangerous for birds: limit its application outside the nest box, avoiding the perimeter of the hole, and allowing it to dry well before installation.
Pressure impregnated wood should not be used with copper arsenate and chromium.
But the good nest boxes are not necessarily made of wood: for example, those of the company Schwegler are made of "wooden concrete", a mixture of cement and sawdust.
Do not have trim in the nest box (straw, moss ...), the birds will bring. However, for large species such as owls or peaks, a layer of sawdust or chips may be placed in the bottom.
Choose a sheltered place
The place chosen should be quiet, rather far from a busy road or road. It is especially important to install the nest box in a place as sheltered as possible from the weather.
The orientations East, South-East or even Northeast are ideal. The nest box should not be exposed all day long to the sun or the permanent shade. Place it away from the prevailing winds, for example behind a bush, avoiding leaves from obstructing the entrance of the nest.
Be careful, the inside of the nest box must remain dry: it is necessary to ensure that the planks are well joined. It is advisable to lean it slightly forward to facilitate the flow of rain on the roof.
The nest box should not be on the trajectory of a trickle of water that would form after a downpour. You can drill a small exhaust hole at the floor to facilitate fluid evacuation.
Avoid wet locations (the presence of moss on trunks or rocks is an unfavorable index). Some birds such as red throats require that the nest box is relatively hidden, for example against a wall where ivy grows.
Protecting it from predators
It is important to install the nest box away from predators (cats, squirrels ...): for example, you can place a wide mesh around the nest box, place spiny branches at the base of the stake or Trunk, plant a rosebush or fix a "stop-cat" around the trunk.
It must be placed at a height, ideally at least two meters from the ground, at least 1.50 meters. Place it preferably against a trunk rather than a branch.
Here are some recommended heights for several species:
- Troglodyte cute (Troglodytes troglodytes): 1,5 meter - 4 meters
- Family Robin (Erithacus rubecula): 1.5 meters - 5 meters
- Song thrush (Turdus philomelos): 1.5 meters - 2 meters
- Gray Wagtail (Motacilla alba): 1.5 meters - 2 meters
- Treecreeper (Certhia brachydactyla): 1.5 meters - 5 meters
- Blackbird (Turdus merula): 1.5 meters - 6 meters
- Green Peak (Picus viridis): 2 meters - 6 meters
- Black Redstart (Phoenicurus ochruros): 2 meters - 6 meters
- Nuthatch (Sitta europaea): 2 meters - 6 meters
- Creche falcon (Falco tinnunculus): 8 meters - 12 meters.
A metal plate placed around the entrance will prevent it from being enlarged by mammals.
For cats to not kill birds in the nest box by entering the leg, the depth should be at least 13 cm from the hole (for circular entry models). For shallow nests, such as those for robins or cockroaches, you can, for example, place a wire net around it.
Caution, predators should not get too close by a well-placed branch or a nearby wall. However, the presence of perches in the vicinity is important because the parents generally do not enter the hole directly.
Install it at any time of the year
It is best to install your nest box in autumn or early winter: it will be spotted by birds before spring. Some species can settle very early (as of late winter), while others like winter troglodytes can spend the winter there.
It is actually possible to set up nest boxes all year round, including in April, May or June, even if those set up later will have less chance of being occupied before the following season. Installing nest boxes spread out over time allows you to target the species you prefer or not: for example, a nest box for Redstart with a white forehead placed before the end of April will prevent it from being occupied by sparrows.
Some birds such as the Gray Flycatcher (Muscicapa striata) return late in their migration (late May), others nest several times during the year and some who have abandoned a nesting site will be delighted to find one available. Finally, your nest box will surely be spotted by birds visiting your garden and these will occupy it perhaps next spring.
The use of a nest can indeed take up to a year, do not lose patience! On the other hand, if a nest box is not occupied two years after its establishment, it is because the place is not suitable.
Install a reasonable number
Avoid placing two nest boxes for the same species too close together; The distance of "safety" varies according to the species: at least 20 meters for small birds and 70 meters for the White-fronted Redstart (Phoenicurus Phoenicurus) and Nuthatch (Sitta europaea).
But you can install several nests of birds that do not compete directly with each other, like fruit-eating and frugivorous species.
For colonial species (sparrows, starlings, swallows), this question of minimum distance does not arise, of course. Nest boxes should be installed as far away as possible from feeders and bird baths.
Limit your visits
Limit your visits. Use binoculars to look away from parents and young people without disturbing them. If you find chicks on the ground, pick them up and put them back in the birdhouse so they are safe.
Clean it at the end of the season
The nest should be easily accessible to be cleaned at the end of the nesting season. Also, prefer models with a removable top for easy cleaning. In autumn, from September, empty the nest box, brush inside, clean it if necessary with water, dry it and apply a pest control product that is safe for birds.
For example, you can use thyme oil. The birds themselves use certain plants to keep pests away (read Some birds use their botanical knowledge to build their nests). Make sure that the boards are tight and that the tie is solid.
Convince the others
Convince your friends, your acquaintances, your company, your association or your town hall to also install nest boxes. Natural cavities are increasingly scarce, and modern buildings offer fewer and fewer bird-friendly sites: you can help them!