The family Oceanitidae known as storm petrels are the smallest of all the seabirds, ranging in size from 13–26 cm in length. There are two similar families of Storm-Petrels; the Hydrobatidae and the Oceanitidae. The Oceanitinae have short wings, square tails, elongated skulls, and long legs. The legs of all storm petrels are proportionally longer than those of other Procellariiformes, but they are very weak and unable to support the bird’s weight for more than a few steps.
Storm petrels are notoriously difficult to identify at sea. Storm petrels use a variety of techniques to aid flight. Most species will occasionally feed by surface pattering, holding and moving their feet on the water’s surface while holding steady above the water. This method of feeding flight is most commonly used by Oceanitinae storm petrels. There are 3 genera and 5 species of the family Oceanitidae known to occur in Peru. Photo: Elliot’s Storm-Petrel.