Elliot's Storm-Petrel is a poorly known seabird of the Humboldt Current off Ecuador, Peru, and Chile. The only confirmed breeding site (O. g. gracilis) is Chungungo Island off Chile. Presumably this subspecies breeds elsewhere off Chile or perhaps Peru, while O. g. galapagoensis likely breeds on the Galapagos, although no nests have been found. While galapagoensis averages larger with more white on the belly, the two subspecies are similar to eachother and to the sympatric Wilson's Storm-Petrel (O. oceanicus). Elliot's differs from the Wilson's in having a white center to the belly (difficult to see) and broad pale patch on the underwing. Like the Wilson's, this species feeds largely on the wing, pattering its feet along the surface and dipping its bill into the water. Birds may gather in mixed flocks with Wilson's Storm-Petrels and other seabirds around ships and cetaceans. This species is also known as "White-vented" Storm-Petrel.