Fészekodú

Fészekodú is a Hungarian term used to describe a nesting cavity, a hollow space in a tree, rock crevice, or a man-made structure that provides shelter and a site for breeding for birds and sometimes small mammals. The word combines fészek (nest) and odú (burrow or hollow), reflecting its dual role as a place for nesting and shelter.

Natural cavities form through decay and insect activity in dead or decaying trees, or are excavated by birds such as woodpeckers. The dimensions and internal shape vary widely, but typical cavities are cylindrical to oval, with a small entrance opening that protects inhabitants from predators and weather. Many bird species are cavity nesters; in Europe, blue tits, great tits, owls, nuthatches, and some small parrots rely on fészekodú-like cavities, either natural or artificial.

Humans often supplement or replace natural cavities with nest boxes or artificial hollows to support biodiversity, particularly in managed forests and urban parks. Access to suitable cavities can be a limiting factor for cavity-nesting species; conversely, excessive removal of decaying trees can reduce available sites.

In ecology, fészekodú is considered a microhabitat component that contributes to species diversity, predator avoidance strategies, and thermal regulation for the inhabitants. The term is more common in Hungarian-language literature and may appear in popular writings on birds and forest ecology.