Friday, December 12, 2014

Which Cormorant is That?


Cormorants are in the Family Phalacrocoracidae, which contains over 40 species. Cormorants are medium to large seabirds and tend to nest in colonies. They have mainly dark plumage and many species have colored skin on the face that is more pronounced during the breeding season.  Their bills are long and thin, and they have webbing between all four toes that helps propel them underwater. Cormorants often spread their soaked wings out to dry after a dive due to incomplete waterproofing that helps reduce buoyancy, a valuable attribute for this species of diving seabirds.

  Pelagic Cormorant In Flight
Photo Courtesy of Susan Glarum


 Pelagic Cormorant In Flight with Nesting Materials
Photo Courtesy of Susan Glarum

 Pelagic Cormorants and Nests on Haystack Rock
Photo Courtesy of Susan Glarum

Haystack Rock is host to three species of cormorants; the Pelagic Cormorant (Phalacrocorax pelagicus), the Brandt’s Cormorant (Phalacrocorax penicillatus) and the Double Crested Cormorant (Phalacrocorax auritu). The Pelagic Cormorant is the species most commonly seen on the rock.

Pelagic Cormorant (Phalacrocorax pelagicus)

The Pelagic Cormorant is one of the smaller of the species with a long body and a long, slender neck. The bird’s slender bill is blunt or hooked at its tip. The non-breeding adults have iridescent, all-black plumage. Breeding birds have two short crests, one on the top of the head and one on the nape. They also have a patch of dark skin below their eyes that turn magenta during breeding season. They feed on fish and marine invertebrates, diving and chasing their prey under water. The pelagic cormorant is among the least social of the cormorants, nesting in loose colonies or far from neighbors. This behavior leads them to nest at the cliff face, usually on ledges. Their nests are built from grasses or seaweed and is held together and adhered to the cliff by the birds’ guano. They tend to return to the same nest site each year, repairing it as necessary each season. They typically have a clutch of three or four eggs; the eggs are typically greenish-white to blue. The Pelagic Cormorant is an abundant and widespread species which can be found in the open ocean during the winter.

 Non-Breeding Pelagic Cormorant
Photo Courtesy of Susan Glarum

Breeding Pelagic Cormorant
Photo Courtesy of Susan Glarum

Brandt’s Cormorant (Phalacrocorax penicillatus)

The Brandt’s Cormorant is a one of the larger species of cormorants, and is found only in marine environments. The bird has short black legs, a long body and neck, with a medium-sized bill that is blunt or hooked at its tip. They have dark plumage with a pale patch at the base of the dark colored bill. Early in the breeding season, the bird has white plumes on its neck and back. Also in the breeding season, adults have turquoise eyes and a bright blue gular pouch, which is very distinct from other cormorants. This blue color fades rapidly after the nesting season. The Brandt's cormorant feeds on small fish and squid from the surface to sea floor, pursuing them by diving using its webbed feet for propulsion. Like the pelagic cormorant, the Brandt's cormorant grabs its prey with its bill, without spearing it. The Brandt’s Cormorant, more social than the Pelagic Cormorant, often roosts and nests in large groups. The bird makes a large nest on gentle slopes or steep cliffs with ledges; the nests are built of grass, moss, weeds, and seaweed and cemented together with the bird’s guano. Clutch size can range from three to six eggs that are pale blue to bluish white. The Brandt's Cormorant is the least vocal of the North American cormorants making sounds that are audible only from a few feet away. In the nonbreeding season the birds redistribute along the coast to locations where food is available. 


Non-Breeding Brandt's Cormorant
Photo Credit: http://www.allaboutbirds.org/guide/Brandts_Cormorant/id

© Maureen Sullivan, Point Lobos, California, June 2012


Breeding Brandt's Cormorant
Photo Credit: http://www.allaboutbirds.org/guide/Brandts_Cormorant/id

© Jason Crotty, CA, Pillar Point, March 2010

Double Crested Cormorant (Phalacrocorax auritu)

The Double Crested Cormorant is a large cormorant and is the most numerous and widespread of cormorants in North America. The bird has short dark legs with a long brownish-black to matte-black body, a small head on a long, kinked neck, with bare orange skin around the face and chin. The bill, about the length of the head, is lighter in color with a strongly hooked tip.  In the breeding season a small plume on either side of the crown, of either black or white feathers, is typically present. The adults will also have turquoise eyes and mouth lining. Its diet is almost all fish, but may include insects, crustaceans, and amphibians. The Double Crested Cormorant floats low on the water's surface and dives to catch small prey. Their nests are built on cliff ledges and are mostly made of finger-size sticks, but may include some seaweed and flotsam. Their nests are also typically lined with grass. They are a social bird typically nesting in colonies, often with other species of wading birds. The clutch size is typically three to four blue eggs.

 Non-Breeding Double Crested Cormorant

Photo Credit: http://www.allaboutbirds.org/guide/Double-crested_Cormorant/id

© Laura Meyers, Greenwood Cemetery, Brooklyn, New York, April 2011

Breeding Double Crested Cormorant
Photo Credit: http://www.allaboutbirds.org/guide/Double-crested_Cormorant/id
© Lorcan Keating, CA, Golden State Park, San Francisco, February 2010
 
References

The Cornell Lab of Ornithology All About Birds Website (allaboutbirds.org)
Seattle Audubon Society BirdWeb Website (birdweb.org)



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