Archilochus alexandri, commonly known as the Black-chinned Hummingbird, is native to North America, particularly the western and southwestern United States, and extends into parts of northern Mexico. Specific regions include states such as Arizona, Texas, New Mexico, and California, with migratory populations reaching as far as the Pacific Northwest and parts of Canada.

The Black-chinned Hummingbird typically inhabits semi-arid regions with desert scrub, riparian woodlands, and open meadows. These areas often feature a mix of bushes, trees, and flowering plants, which provide nectar and insects for feeding. The climate in these habitats ranges from hot and dry in desert regions to mild and moist in riparian zones, with seasonal variations in temperature and precipitation.

As a nectarivorous bird, the Black-chinned Hummingbird primarily feeds on nectar from flowering plants but also consumes small insects and spiders for protein. Its ecological niche involves pollination, as the bird assists in the transfer of pollen while feeding. The species exhibits territorial behavior, often defending feeding areas vigorously, and adapts to diverse habitats by utilizing available floral resources.