Expanding our knowledge of the nesting sites of Northern Storm-Petrels (Hydrobatidae) in northern Chile is a first step in determining their vulnerability to actions that affect their population dynamics. Globally, the Markham’s Storm-Petrel (Hydrobates markhami) and the Ringed Storm-Petrel (H. hornbyi) are categorized as Near Threatened. In the Atacama Desert, previous research reported their use of flat areas devoid of vegetation as nesting microhabitat, where they take advantage of cavities in dry soil to breed. We report a new breeding colony and describe the nest attendance patterns of 2 storm-petrels in the vicinity of a fog oasis with the abundant vegetation characteristic of the hill formations of the coastal Atacama Desert, which constitutes a new nesting microhabitat for these species. Our adult nest attendance records document a daily pattern of nocturnal activity, where parents depart from nests in search of food before dawn and return during the night. The discovery of this new microhabitat for 2 endangered birds supports the protection of fog oases in the Atacama Desert, an ecosystem facing substantial threats.