The Brandt's cormorant is a seabird found only in North America with a range along the coast from Alaska to Mexico. San Miguel Island, the westernmost island in Channel Islands National Park, is home to the most important breeding colony of this species in Southern California.
Quick and Cool Facts
- Brandt's comorants breed along the Pacific Coast from Alaska to Mexico.
- Their main breeding range is between California and Washington.
- Brandt's cormornats nest in colonies on the ground including cliffs, islands, and offshore rocks.
- The male cormorant selects the nest site and brings the nesting materials to the female so she can build the nest.
- Brandt's cormorants are great divers and they can dive as deep as 40 feet in their pursuit of prey.
- Their webbed feet propel them underwater so they can swim and feed on fish close to the bottom.
- During the breeding season, they have an expandable pouch on their throat that turns blue.
Brandt's cormorants weigh about 4.6 pounds and measure 34 inches in length, with a wingspan of about 4 feet. Sexes look similar; with short black legs, a long black body and neck, and a dark bill with a hooked tip. Breeding adults have brilliant turquoise eyes and a bright blue gular pouch-distinctive among this species of cormorant-which fades quickly after the nesting season. Their breeding plumage also includes white plumes on either side of the head, neck, and back. Like other cormorants, Brandt's cormorants often spread their wings out to dry after a dive, as their feathers are not completely waterproof and become soaked. This helps reduce buoyancy and allows the cormorant to forage deep under water.
Brandt's cormorants breed along the Pacific Coast from Alaskasouthern British Columbia southward to Baja California. All five islands in the Channel Islands National Park provide breeding sites. In the main part of their range, from California to Washington, the cormorants rely upon food sources produced by the upwelling of the California Current. In the non-breeding season, the effects of this current diminish, and Brandt's cormorant populations redistribute along the coast from southern Alaska southward to Baja California, wintering wherever food is locally available.
Brandt's cormorants are exclusively marine, inhabiting inshore Pacific coastal waters, especially kelp bed areas; as well as large bays, estuaries, or coastal lagoons. Their preferred breeding location is on gentle slopes on the windward side of islands. They may forage either near shore or well out to sea.
The Brandt's cormorant diet consists predominantly of a wide variety of fish, including herring and rockfish, as well as shrimp, and crabs. This cormorant, sometimes feeding in groups, can dive deeply from the surface (capable of reaching over 100 meters) and pursues fish underwater, propelled by its powerful webbed feet. The bird snatches prey with its bill, rather than spearing it.
Brandt's cormorants breed on all of the islands of Channel Islands National Park, although San Miguel Island is the most important. The latest survey shows 4200 pairs in the entire park. This species is colonial, nesting with other Brandt's cormorant, and in California, with the common murre. Male cormorants choose the nest site and display there, inflating the blue throat pouch while pointing the head and tail skyward. The males are also responsible for nest building. They make a substantial nest on the ground, consisting of dry matter like weeds, grass, sticks, or marine debris all cemented together with droppings.Seaweed is collected by diving and is also used as nesting material. The female cormorant usually lays 3 to 6 pale blue eggs. Cormorant hatchlings are naked and helpless. Both parents care for the chicks, feeding by regurgitation, brooding chicks when cold, and shading them when hot. Chicks often congregate in groups called crèches once parents stop attending nests continously, but they return to their own nests to be fed.
Brandt's cormorants are primarily permanent residents, with some local movement. For example, Farallon Island birds migrate to the adjacent mainland. They may wander along the Mexican coast in winter, south of their breeding range, but never inland.
Brandt's cormorant colonies vary from year to year, both in size and location. In California, Channel Islands National Park, as well as refuges and ecological reserves, serve as protected areas. Persistant challenges to Brandt's cormorant include pesticides and oil pollution. During the incubation period, Brandt's cormorant are vulnerable to disturbance from fishing, diving, boating, and even visitation for research or educational purposes, which can result in near-total egg loss and colony desertion. El Nino's ocean warming effect has also negatively impacted populations. Research suggests that, given good ocean conditions and public access restrictions, Brandt's cormorants can persist even in high-disturbance areas. The population size is very large, and hence does not approach the thresholds required for listing as a vulnerable species. For these reasons the species is evaluated as Least Concern in BirdLife International (2011) IUCN Red List for birds.