Hydrobates pelagicus; the storm petrels are small black sea birds (about 15 cm), very similar to the Leach's Petrel. It is just slightly smaller and deeper black than the Leach's petrel. Also the white parts of the body between the wings and tail is larger and more pronounced that in the Leach's petrel. In flight they show a white streak on the bottom of the wing that is missing on the Leach's petrel wing. They tend to fly more in straight lines where Leach's's petrel flies more in a dancing fashion. When flying close above the water they use their feet to add a running motion to flying. Their main breeding grounds on Iceland are on the Vestmanneyar isles. They forage during the day and return to their nests at night to feed the chicks. In autumn they return to their winter residences, the southern Atlantic.