About the black cormorants;
All are fish-eaters, dining on small eels, fish, and even water snakes. They dive from the surface, though many species make a characteristic half-jump as they dive, presumably to give themselves a more streamlined entry into the water. Under water they propel themselves with their feet, though some also propel themselves with their wings. Some cormorant species have been found, using depth gauges, to dive to depths of as much as 45 metres.