Cormorants date back to ancestors from the time of the dinosaurs and are rather prehistoric looking. Their average body weight is up to 11 pounds, with a wingspan ranging from 18 to 39 inches. They are more comparable to pelicans and penguins than other birds.
The six species native to North America are the double-crested cormorant, the great cormorant, Brandt’s cormorant, the red-faced cormorant, the neo-tropic cormorant, and the pelagic cormorant.
Cormorants, which are from the family Phalacrocoracidae, are often known differently elsewhere. In different areas of the world, they are known as shags, which refers to the crests that some have. For instance, the great cormorant in North America is known as the black shag in New Zealand.
Cormorants and shags are in a group called non-passerines. They can easily be distinguished from passerines or perching birds as they rarely perch as they are too large.
They are also classed as diving birds, and some can dive up to 150 feet. They are outstanding fishers with the help of hook-shaped bills that are serrated and long.
Their diet consists of shrimp, crab, crayfish, salamanders, eels, snakes, herring, tadpoles, frogs, and various insects. The diet varies depending on their territory in North America, whether coastal or inland.
The six different cormorant species in North America seem to have a few things in common where breeding is concerned. They all nest mostly in colonies. Both males and females incubate the eggs, and both feed the young.
In some species, the male builds the nest, while in others, the female. Breeding takes place between three and five years depending again on the species.
Cormorants are mostly quiet birds. They do emit deep grunts that resemble the oink of a pig. These vocalizations are usually made during mating, aggressive skirmishes, flight, and landing.
Cormorant populations have risen over the years in North America. This is due to the decrease in the use of certain pesticides. These caused the breakage of the eggs and deformities to occur in hatchlings.
There has been a significant rebound in cormorants and many other species since some pesticides were banned.
There are 38 species of cormorants residing throughout the world, and six that breed in North America.
The six species native to North America include the double-crested cormorant, the great cormorant, Brandt’s cormorant, the red-faced cormorant, the neo-tropic cormorant, and the pelagic cormorant.
The double-crested cormorant is most frequently spotted and more far-reaching than the other species and can be found inland. They range from Alaska, Newfoundland, New England, and south to the Bahamas.
They are all-dark with a golden sheen on their wings. They can be distinguished from other species by their orange face, as the two crests are hard to spot. They grow from 30 to 36 inches making them one of the largest cormorants.
They are silent birds, except when breeding, taking off, or landing. They then emit a low grunt. They can be found around lakes, rivers, and coastal waters.
They lay 2 to 7 greenish-blue eggs in a nest that can sometimes be found in a tree. The double-crested cormorant is North Americas only regular freshwater species.
The great cormorant is the largest of the cormorants, measuring 35 to 40 inches. They are dark with green and gold iridescent plumage. They have a white chin and flank patches in summer.
The great cormorant has a larger head and bill than other cormorant species. They can often be seen with their wings out while perching, usually to dry them.
They can be seen along the coast of the Atlantic from Florida all the way to Labrador.
They breed on Canada’s coast, where they lay 3 or 4 eggs, pale blue in color. They nest in piles of seaweed on open ledges or at the foot of a cliff. Incubation lasts 28 to 29 days and is shared by the male and female.
Brandt’s cormorant gets their name from the German naturalist Johann Friedrich von Brandt who described the bird from specimens.
This species is black with a blue throat patch, surrounded by a border of dull cream. They have no crest, and their plumage is iridescent.
Brandt’s cormorant resides along the Pacific coast to the south of Alaska, breeding from southern British Columbia to Mexico. They can only be found along the Pacific coast.
They breed between April and May and lay between 3 to 6 pale blue eggs. Incubation is shared between the male and female. Nests are made from seaweed and twigs on the ground.
Brandt’s cormorant can be heard to grunt and also croak on occasion. They grow between 33-35 inches.
The red-faced cormorant is resident in Southern Alaska and the Aleutian Islands and is a close relative of the Pelagic cormorant.
They are medium-sized, growing from 30-32 inches. They are all dark, with a green-sh blue, with purplish-bronze on the sides and flank. They have a red face and a yellow bill. They can be identified as breeding by white flank patches and a double crest.
They can be heard grunting and growling when breeding.
The neo-tropic or olivaceous cormorant can be found in Southern Texas to Mexico and Louisiana, New Mexico, and even remotely in the Great Plains.
They are a small species with dark olive plumage. They have an orange-yellow throat patch surrounded by white. They grow between 23 – 25 inches.
Although they are the smallest cormorant on the Atlantic coast, they have a long tail.
They are generally silent birds but do grunt when breeding. They can be found in freshwater, lagoons, and marshes.
They make their nest from twigs and grass, which they place in rocks or trees. They lay between 2 to 6 eggs, which are pale blue.
Although size varies from species to species, the pelagic cormorant is the smallest cormorant on the Pacific coast, where it breeds. They grow from 25-30 inches
They are all-black with a thin neck and bill. They have a red face with a double crest, which can sometimes be seen in the field.
When breeding, they make a low grunting sound but are generally silent. They can be found mainly along the Pacific coast, preferring sheer cliffs along the coast.
Although their name suggests they live in the open sea, they are coastal birds.
They lay between 3 to 7 eggs, pale blue in a nest made of grasses, sedges, and seaweed. They make their nest on cliffs with narrow ledges.
For more information on cormorants and other birds in North America, I recommend the following field guides.