The Willow Warbler (Phylloscopus trochilus) is native to Europe and Asia. It has a broad geographical distribution across these continents, particularly prevalent in temperate regions.

The Willow Warbler thrives in a variety of habitats, including woodlands, forests, and areas with abundant shrubs and trees. It is commonly found in deciduous forests during the breeding season. The species prefers temperate climates but can also be found in boreal zones and mixed forest environments.

In its ecological niche, the Willow Warbler primarily feeds on insects and spiders, playing a critical role in controlling insect populations. It is a migratory bird, spending the breeding season in Europe and northern Asia, and migrating to sub-Saharan Africa for the winter. This migratory pattern influences its habitat preferences, requiring suitable environments for feeding and breeding in different regions.