About Oceanodroma microsoma (Coues, 1864)
The least storm petrel (scientific name Hydrobates microsoma, formerly classified as Oceanodroma microsoma) is a small seabird belonging to the storm petrel family Hydrobatidae. It measures 13–15 cm in length, with a wingspan of 32 cm, and is the smallest species in the order Procellariiformes. It was previously placed in the genus Oceanodroma before this genus was synonymized with Hydrobates. This species breeds on islands off the Baja Peninsula and Gulf of California, Mexico, where it nests in rock crevices or small burrows dug in soft earth. It lays a single egg per breeding attempt; the egg is primarily white, with a wreath of fine black specks around one end, and sometimes both ends. Like most petrels, it can only walk by shuffling a short distance to its burrow, and it nests in colonies. When not breeding, it lives entirely at sea, ranging as far south as tropical Pacific coastal South America. It is frequently seen well offshore of southern California in late summer and autumn. It feeds mainly on planktonic crustaceans, with a particular preference for spiny lobster larvae. It feeds in the same manner as other storm petrels, picking food from the water surface while flying. On some of its breeding islands, the least storm petrel experiences population losses, mainly caused by feral cats and rats.
