cavitynesting

Cavity nesting, also written cavity-nesting, is the behavior of using or creating nest sites in cavities such as tree hollows, rock crevices, or man-made structures. It is common among birds and some other animals and provides protection from weather and predators during reproduction and chick rearing. Cavities can be natural, created by decay, fire, or other processes, or excavated by the inhabitants themselves, most notably woodpeckers.

Many species are secondary cavity nesters, meaning they rely on holes made by others, while a smaller set are primary cavity nesters that excavate their own holes. Tree age and structure influence cavity availability; old forests with standing dead wood harbor more hollows, but modern managed forests often have fewer. Cavities also occur in rock fissures, holes in buildings, or artificial nest boxes placed by people.

Competition for limited cavities can shape community dynamics. Primary cavity makers create openings that later host other species. Nest site characteristics such as entrance diameter, depth, temperature, and microclimate affect suitability for different species. Predation, brood parasites, and competition can influence occupancy and survival.

Conservation and management efforts include preserving dead trees and snags, protecting old-growth habitats, and providing nest boxes designed for target species. Proper placement, predator guards, and regular maintenance reduce box failure. In urban and agricultural landscapes, cavity-nesting birds can benefit from adaptable nest boxes, while invasive species and disease risk require monitoring.

While most commonly discussed in birds, cavity nesting also occurs in some mammals, bees, and other organisms that use hollow structures for rearing young. The study of cavity nesting informs forest management, biodiversity in urban areas, and our understanding of ecological dependencies.