Phalacrocorax auritus
This prehistoric-looking bird is the only North American cormorant that is commonly seen in the Rockies. Double-crested Cormorants are often observed with their wings partially spread, drying their flight feathers in the sun and wind. Cormorants lack the ability to waterproof their feathers, which helps them during underwater dives by decreasing their buoyancy. Also aiding the Double-crested Cormorant's aquatic lifestyle are its long, rudder-like tail, its excellent underwater vision and its sealed nostrils. Because these birds cannot breathe through the nose, they can often be identified by their gaping beaks. In South America, cormorants are economically valuable to local people, who mine the birds' guano (excrement) for commercial fertilizer. |
I.D.: Sexes similar: large, black water bird; long tail; long neck; thin bill, hooked at the tip; blue eyes. Breeding: throat pouch becomes intense orange-yellow; fine, buff plumes trail from the eyebrows. Immature: brown upperparts; buff throat and breast; yellowish throat patch. In flight: rapid wing beats; kinked neck. Size: L 26-32 in. (66-81 cm); W 52 in. (132 cm). Range: local but common breeder in Idaho and western Montana, in suitable wetland habitat. Habitat: Summer: Yellowstone Lake. In migration: large lakes and large, meandering rivers. Nesting: colonial; on low-lying islands or precariously high in trees; nest platform is made of sticks, aquatic vegetation and guano; often nests on islands with pelicans, terns and gulls. Feeding: long underwater dives of up to 30 ft. (9 m) after small schooling fish or, rarely, amphibians and invertebrates; young are fed by regurgitation. Voice: generally quiet; occasional grunts or croaks. Similar Species: Common Loon: more colorful; shorter neck. Canada Goose: white cheek; not completely black. White-winged Scoter and Surf Scoter; shorter necks; shorter tails. |
