Bird house

A nest box, also spelled nestbox, is a man-made enclosure provided for animals to nest in. Nest boxes are most frequently utilized for birds, in which case they are also called birdhouses or a birdbox/bird box, but some mammalian species may also use them. Placing nestboxes or roosting boxes may also be used to help maintain populations of particular species in an area. The nest box was invented by the British conservationist Charles Waterton in the early 19th century to encourage more birdlife and wildfowl on the nature reserve he set up on his estate.

Nest Boxes or Birdhouses are getting more and more attention than before. This is because the industrialization, deforestation and other human activities since the mid of the 20th century have severely declined their natural habitats, introducing hurdles in their breeding, in such a case a Nesting box is a life savoir in preventing these precious birds from extinction.

Construction
General construction
Nest boxes are usually wooden, although the purple martin will nest in metal. Some boxes are made from a mixture of wood and concrete, called woodcrete.Ceramic and plastic nestboxes too are not suitable.

Nest boxes should be made from untreated wood with an overhanging, sloped roof, a recessed floor, drainage and ventilation holes, a way to access the interior for monitoring and cleaning, and have no outside perches which could assist predators. Boxes may either have an entrance hole or be open-fronted. Some nest boxes can be highly decorated and complex, sometimes mimicking human houses or other structures. They may also contain nest box cameras so that use of, and activity within, the box can be monitored.

Bird nest box construction
The diameter of the opening in a nest-box has a very strong influence on the species of birds that will use the box. Many small birds select boxes with a hole only just large enough for an adult bird to pass through. This may be an adaptation to prevent other birds from raiding it. In European countries, an opening of 2.5 cm in diameter will attract Poecile palustris, Poecile montanus; an opening of 2.8 cm in diameter will attract Ficedula hypoleuca, and an opening of 3 cm in diameter will attract Parus major, Passer montanus, an opening of 3 cm in diameter will attract Passer domesticus.

The size of the nest box also affects the bird species likely to use the box. Very small boxes attract wrens and treecreepers and very large ones may attract ducks and owls. Seasonally removing old nest material and parasites is important if they are to be successfully re-used.

The material used in the construction may also be significant. Sparrows have been shown to prefer woodcrete boxes rather than wooden ones. Birds nesting in woodcrete sites had earlier clutches, a shorter incubation period, and more reproductive success, perhaps because the synthetic nests were warmer than their wooden counterparts.

https://en.wikipedia.org/wiki/Nest_box