Treenester

Treenester is a term used to describe organisms that breed or roost in trees, especially those that utilize tree cavities, hollows, or forks in branches. It is applied in ecological and wildlife management contexts to distinguish arboreal nesting and cavity-nesting species from ground-nesters or those that nest in other habitats. The term is not universally standardized and may be used informally, with researchers sometimes specifying the taxa or nesting niche involved.

Habitat and behavior

Treenesters rely on structural features of trees, such as natural hollows, dead wood, broken trunks, and thick bark crevices. These features can be produced by decay, fire, storm damage, or fungal activity. The availability of suitable nesting sites influences reproduction, survival, and community structure, and treenesters often require multiple trees to meet nest sites, for roosting, and for foraging.

Examples

Birds commonly described as treenesters include woodpeckers, tits and chickadees, nuthatches, and various owls. Mammals such as flying squirrels and red squirrels may use tree cavities for shelter and reproduction. Bats frequently roost in tree hollows and crevices. In tropical regions, some primates also use arboreal hollows as nesting or sleeping sites. Insects may inhabit galleries within living or dead wood.

Ecological significance and management

Because many treenesters depend on tree cavities, maintaining or enhancing a forest’s legacy of large or decaying trees is important for biodiversity. Conservation measures often include retaining snags, avoiding excessive pruning, and providing artificial nest boxes for select species to mitigate cavity scarcity in managed landscapes.