Poecile rufescens, commonly known as the Chestnut-backed Chickadee, is native to the Pacific coastal regions of North America. Its geographical distribution extends from southern Alaska through western Canada and down to the coastal ranges of the United States, including Washington, Oregon, and northern California.

The Chestnut-backed Chickadee inhabits coniferous forests, particularly those composed of Sitka spruce, Douglas fir, and western hemlock. These regions are characterized by a temperate maritime climate with cool, wet winters and mild summers, providing a consistent supply of food resources and shelter.

As a small passerine bird, the Chestnut-backed Chickadee occupies an ecological niche as both a seed disperser and insect predator. It forages in the understory and canopy layers of forests, feeding on insects, caterpillars, and seeds, contributing to pest control and the dispersal of plant species. The species is well adapted to these environments, exhibiting behaviors such as mixed-species flocking during the non-breeding season to enhance foraging efficiency.