The Family Pelecanoididae consists of small, diving seabirds known as diving-petrels, found mainly in the Southern Hemisphere, particularly around subantarctic islands. These birds are highly adapted for underwater feeding, with short wings used for "flying" through water and a streamlined body for diving after small fish, plankton, and crustaceans. They typically nest in burrows on coastal slopes or islands, laying a single egg per breeding season. Despite their resemblance to auks, diving-petrels are distinct in taxonomy and behavior, and they play an important ecological role in marine food webs as mid-level predators.