1. The preparation or construction of nests and the behavior connected with it: Although many mockingbirds and insects build their nests in trees, several animal species practice nidification and burrow or dig holes in the ground for their dens.

The term nidification is used in zoology and involves all the preparations for the reception of eggs or newborn animals and for their care.

Smaller species of birds provide more elaborate nidifications; such as, the abodes in hedgerows or bushes, or even on the ground where bowl-shaped structures are made of fine grass that is interwoven with horsehairs and moss or lichen so the refuges are not easy to see.

The thrushes use a foundation of clay and line the insides of their domiciles with a mixture of decayed wood and cow dung.

2. Etymology: from Latin nidus, "nest" + facere, "to make".