Thursday, February 11, 2010


Cormorants are big black water birds with long necks. They dive for a living, and they float low in the water, with bill pointing up, while at the surface. All of them have all four toes connected by webs, characteristic of the Pelecaniformes, the avian order that includes pelicans and boobies. The bill is prominently hooked at the end, a “tool” to subdue the slippery fish they catch. All three species are fish-eaters, chasing down their prey with amazing underwater speed. At close range, their emerald-green eyes are a pleasant surprise.

Three species of cormorants inhabit Pacific Northwest waters. Two of them—Brandt’s and Pelagic—are entirely marine, and it would be a surprise to see either of them on fresh water at any time. The third—Double-crested—is one of the world’s more successful birds, occurring on all large water bodies, fresh and salt, all across the Northwest as well as throughout North America below the boreal zone. The other two species range along the Pacific coast.

Double-crested Cormorant (Phalacrocorax auritus) is the largest of the three and can be recognized by its yellow-orange face skin and throat pouch and somewhat pale bill. The feathers of the upperparts are very dark brown with black edges, producing a chevron pattern on the back. In breeding season, the adults have side-by-side curly crests. Immature Double-crests are the only cormorants that are pale beneath, the underparts becoming increasingly dark with age until they mature at three years.

Brandt’s (Phalacrocorax penicillatus) is a bit smaller, with a more slender bill, head, and neck and a distinctly shorter tail. The throat pouch is dark but becomes brilliant sky-blue in breeding season. The buffy patch around that can be seen all year. The back is glossier than that of the Double-crested, and the breeding plumes are white, arrayed along the neck and back. Immatures are dark brown above and a bit paler below but otherwise look like nonbreeding adults.

Pelagic (Phalacrocorax pelagicus) is much smaller than the other two, only half the weight of Double-crested, with a small head and very slender bill and neck. The plumage is iridescent, glossy green and purple. The tail is long, even longer than that of the Double-crested relative to the bird’s size. The throat pouch is dark, but the facial skin becomes red during the breeding season, fore-and-aft crests develop on the head, and a big patch of white feathers appears on either side of the tail base. Immatures are very dark brown, almost as dark as adults.

Breeding plumage in all species comes very early, so by February you can see signs of it, and they become easier to identify. After the birds are on their nesting colonies, even while still incubating eggs, they begin to molt the characteristic breeding plumage and are out of it by July or August.

At a distance, the three species can be difficult to identify, but the pale bill and throat of the Double-crested and the small size and glossy plumage of the Pelagic distinguishes them if they are anywhere near one another. And they often are, as they roost on pilings and rocks together all over Puget Sound. Double-crested is almost always much more common and usually perches higher than Pelagic. Brandt’s is less common in Puget Sound but still widespread in winter and often roosts with the other two. It looks about as large as the Double-crested but has a dark bill and throat and obvious short tail. Its head feathers often look puffy, in contrast to the flat head of the Pelagic.

Double-crested is the only one of the three that habitually spreads its wings to dry them as soon as it perches. One of the big puzzles in cormorant biology is why this behavior differs in birds with such similar habits and anatomy! Student research with salvaged cormorant carcasses at the Slater Museum was unable to find any difference in wetting or drying parameters in the three species.

In flight the Double-crested shows a thick, crooked neck. The Brandt’s neck is thinner and sometimes shows the crook but less pronounced. The Pelagic’s neck is straight, and the head is scarcely distinct from the neck. The shorter tail of the Brandt’s again is a good identifying mark. Double-crested often fly very high and often over land, probably going between lakes or between fresh and salt water, while the other two tend to fly just over the water. The two large species sometimes fly in small groups, usually arranged in a line; Pelagics fly by themselves or occasionally join groups of Brandt’s.

Cormorants in general feed on bottom fish such as sculpins, soles, and gunnels, which they pursue in all marine habitats. Pelagics tend to be more associated with rocky areas, Double-crested everywhere. Brandt’s tend to feed in open water on surface and midwater schooling fish such as herring and sand lance. Both of the larger cormorants often collect in groups to feed on abundant fish, while Pelagics tend to forage singly.

The most exciting way to view cormorants is at a breeding colony. All three breed in Washington, Brandt's on cliffs at the mouth of the Columbia River and the other two widely on cliffs (Pelagic) or islands (both) on the outer coast and in protected waters, south very locally into Puget Sound. The birds wave their heads around and hiss and grunt at one another, and their reptilian ancestry seems beyond debate. They lay 3-4 chalky white eggs and incubate them for about a month, then the young take another month and a half or more to leave the nest. Both parents participate fully in care for the young.

Dennis Paulson