Small and often confused as decorative seeds of an unknown plant species, Nilby eggs are laid during late October throughout mid November. They are kept warm by being wrapped in the mother's leafy cloak before being buried. Once buried underground at the base of the tree being used as a nest, these eggs will remain dormant until spring arrives.
Nilby make their nests inside large trees by creating an extensive tunnel system. Unfortunately this will eventually kill the tree. However, Nilbies are rather small, only about the size of a child's hand, so many different Nilby families can share one tree together which keeps them from killing off swathes of forest. The dead tree not only serves as a Nilby's home but as its source of food as well. Nilby primarily eat the fungus that begins to grown on the outside and insects that try to infest the insides of their trees. So despite the tree being dead, it decays very slowly as the Nilby families slow down the decomposition process.