 However, there are also reports of foraging in flocks, and this is more usually seen in cormorants that feed in mid-water.The birds are highly gregarious, with roosting flocks of 250,000 having been reported, and flocks of up to 25,000 at sea.Some authors, such as Paul Johnsgard, place this species, along with a number of other related cormorants, in a genus "Leucocarbo".