Oceanodroma leucorrhea; the Leach's storm-petrels are small black sea birds, but slightly larger than the storm petrel (about 20 cm) and they have relatively longer and more forked wings. For other differences seethe card of the European Storm-petrel. Their main breeding grounds on Iceland are on the Vestmanneyar isles. However they are not that common in Europe. larger populations are found on the southern hemisphere. They forage during the day and return to their nests at night to feed the chicks. The European populations spend the winter on the South Atlantic.