The Mourning Warbler, Geothlypis philadelphia, is a small songbird found in dense thickets and regenerating forests across North America. It has a distinctive olive-green back, gray hood, and yellow underparts. Known for its elusive nature, it is often heard rather than seen, with a melodic song that signals its presence.

The Mourning Warbler (Geothlypis philadelphia) is native to North America, specifically in the northeastern United States and southeastern Canada. During the breeding season, it is found across regions such as the Great Lakes area, extending through parts of New England, and into eastern parts of the Canadian provinces like Quebec and Ontario.

The Mourning Warbler typically inhabits dense understory of mixed or deciduous forests, often in areas that have been recently disturbed such as clearcuts or areas recovering from natural events like fires or storms. These environments provide the tangled thickets and ample ground cover that the species prefers for nesting and foraging.

As a ground-nesting insectivore, the Mourning Warbler occupies a niche within these dense forest understories where it feeds on insects and spiders. It plays a role in controlling insect populations and contributes to the ecological dynamics of forest regeneration by inhabiting early successional habitats.