28-1-2016 ALBUFERA, VALENCIA - EURASIAN GREAT CORMORANT (Phalacrocorax carbo)

Along the shorelines of northeastern North America, burly Great Cormorants mix in with slimmer, more abundant Double-crested Cormorants. These large-billed, blocky-headed cormorants have a white throat patch and in breeding season a white patch on the thigh. They feed mostly on bottom-dwelling fish captured during dives. Like other cormorants their plumage has limited waterproofing, and they often stand on rocks with their wings outstretched to dry. In the water, soggy feathers may be a bonus and not a liability, making the birds less buoyant during their dives.

In North America, Great Cormorants live mainly in saltwater environments, although in recent decades they have begun to winter on large rivers such as the Hudson and the Delaware. Rocky headlands in New England or Atlantic Canada are optimal places to find Great Cormorants, but almost any rocky shoreline within their range could host them, including jetties, breakwaters, and islands. They tend to form smaller flocks than the more numerous Double-crested Cormorant.

People have used cormorants to help them fish for centuries. In 5th century China and Japan, and 16th century Europe, fishermen fitted tethered rings loosely around the birds’ necks, keeping them from swallowing larger fish. Cormorants live a long time, and some of the older cormorants would keep fishing even without the rings and tethers. Into the 20th century in Macedonia and Greece, fishermen used captive cormorants to herd fish toward their nets.

Great Cormorants often hold the wings open when they are out of the water. They typically face into the wind and turn their backs to the sun. This behavior probably serves to warm them and help dry the plumage. It may also aid in the digestion of prey.

Great Cormorants are found throughout the world, but outside of North America they inhabit mostly freshwater rivers and lakes.

The claw of the Great Cormorant’s middle toe is pectinated, or serrated like a comb. It’s thought that the birds use this for preening the plumage.

The oldest Great Cormorant ever recorded was a male in Denmark that was at least 22 years old. In North America, the oldest Great Cormorant was a bird banded in Quebec as a nestling and found in Nova Scotia in 1951, when it was 14 years, 4 months old.