Northern storm petrels are a group of the smallest seabirds, comprising the family Hydrobatidae within the order Procellariiformes. They are typically found in the Northern Hemisphere and are known for their fluttering, bat-like flight patterns as they feed on crustaceans and small fish at the ocean's surface. These birds are expert fliers, often hovering or "walking" on the water's surface using the wind to stay in position. They are pelagic, which means they spend most of their lives at sea and only come to land to breed. Loyal to their birth colonies, storm petrels are nocturnal visitors to their nest sites, where they engage in monogamous and long-term breeding partnerships, sharing duties like incubation and chick-feeding. Their reproductive cycle is lengthy, with incubation lasting up to 50 days, and fledglings taking an additional 70 days. Sadly, some storm petrel species are threatened by human encroachment, particularly by invasive predators on what were once mammal-free island breeding grounds. The Guadalupe storm petrel is believed to be extinct due to such pressures. The taxonomy of storm petrels is complex, with the family Hydrobatidae itself being refined over time through DNA analysis, which has identified several distinct species and led to the merger of the once-distinct genera Hydrobates and Oceanodroma. Physical traits such as grey or dark plumage with white rump patches, forked or wedge-shaped tails, and longer wings distinguish storm petrels. Identifying these birds at sea is notoriously challenging due to their varied appearances and the prevalence of incorrect information. Their diets are not well-documented but generally revolve around crustaceans, supplemented by fish and molluscs. Storm petrels exhibit diverse migration patterns; some species travel vast distances post-breeding, while others are more sedentary. Breeding occurs in colonies, often on isolated islands where they nest in burrows or crevices, displaying strong site fidelity. Their cultural significance is notable, seen as omens of stormy weather, and historically they have been associated with sailors' lore and revolutionary symbolism in literature and politics. Their conservation is critical as they face growing threats such as habitat degradation and predation by invasive species.