Carbo auritus Lesson, 1831, North America. Four subspecies.
OTHER COMMON NAMES
French: Cormoran а aigrettes; German: Ohrenscharbe; Spanish: Cormorбn Orejudo.
Body length of 33 in (83 cm), with a bright yellow bill, yellow cheek pouch, blue eyes, glossy blackish plumage, black legs and feet, and males somewhat larger than females.
The most widely distributed cormorant in North America, occurring on both the Pacific and Atlantic coasts, in the Caribbean Sea, and on many larger inland lakes and rivers.
Usually nests on islands and feeds in coastal waters and in large lakes and rivers.
A highly social species that breeds in colonies and aggregates in flocks; it catches its prey by underwater pursuit.
FEEDING ECOLOGY AND DIET
Feeds on small fish, crayfish, squid, and other crustaceans.
Lays three to four eggs in a crude stick-nest located in a tree, with both sexes sharing the incubation (c. 25–29 days) and rearing of the chick.
Not threatened. Abundant over much of its range. However, this species was considered at risk in some states in the 1970s due to organochlorine-pesticide-induced egg-shell thinning and population declines. These populations are now increasing in numbers following bans on the use of these chemicals.
SIGNIFICANCE TO HUMANS
In some parts of its range it is considered a pest for “eating too many fish” and because it kills its nesting trees with its caustic excrement.
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