Thursday, April 25, 2013

Thick-Billed Murre


Thick-Billed Murre

 
Uria lomvia


Photo: Murres atop a rock
Thick-billed and thin-billed murres rest on a rock in the sun on Gull Island in Alaska. Thick-bills are recognizable not just by their slightly heavier bills but also by the white line down the sides of the bill.
Photograph by Michael Melford
The thick-billed murre swims far better than it flies. Takeoff is awkward, but once it's airborne, it can fly at about 75 miles an hour (120 kilometers an hour). Among the deepest underwater divers of all birds, it uses its stubby wings to "fly" through the water, routinely reaching depths of more than 330 feet (100 meters)—sometimes even twice that—in pursuit of the fish, squid, and crustaceans it feeds on.
Covered in black feathers on its head, back, and wings and white feathers on its breast and underside, this waterbird can be found in and around Arctic waters. In the summer it breeds off the rocky coasts of Alaska, Canada, Greenland, Scandinavia, and Russia. But in winter—when it's not breeding—the thick-billed murre is at sea, off the edge of open ice southward to Nova Scotia and northern British Columbia. It also winters off the coasts of Greenland, northern Europe, and southward in the Pacific Ocean to northern Japan.
The thick-billed murre doesn’t build nests. Instead, the female joins others of her species in a large, noisy colony and lays a single egg on a narrow cliff ledge. She then arranges pebbles and other debris close to the egg, cementing them with feces to form a support that prevents the large egg from rolling off the ledge if it dislodges. The egg hatches in 30 to 35 days. Both parents feed the chick, caring for it until it fledges at about 21 days old. At this time, chicks make a migratory journey that is unique among birds, swimming as far as 620 miles (1,000 kilometers) in the first leg to their wintering grounds off the coast of Newfoundland.


Friday, April 19, 2013

Canvasback


Canvasback

 
Aythya valisineria


canvasback-diver-duck.jpg
Canvasbacks are diver ducks well equipped with their own form of flippers—large webbed feet that make them smooth and graceful swimmers.
Photograph by Jac6.Flickr, Flickr
Canvasbacks are diver ducks well equipped with their own form of flippers—large webbed feet that make them smooth and graceful swimmers. They spend much of their time in the water and use their long bills to feed by digging through bottom sediments in search of aquatic plant stems and roots, or submerged insects, crustaceans, and clams.
On land, canvasback movements are clumsy and the ducks seldom stray too far from the water’s edge. But when “cans” take to the air they can cover a lot of ground.
Each year when winter weather begins to chill northern lakes, ponds, and prairie wetlands, the canvasbacks’ food becomes scarce and the ducks take flight in enormous flocks. Thousands of birds migrate together each year to traditional wintering sites like the Chesapeake Bay, San Francisco Bay, Gulf Coast, and Mexico. The majority of North American canvasbacks breed in the Prairie Pothole wetlands and migrate via the Mississippi Flyway to the Mid-Atlantic and Lower Mississippi Alluvial Valley, or along the Pacific Flyway to the California coast.
The Chesapeake Bay’s Susquehanna Flats area was once the winter home of perhaps half of the North American canvasback population. But the shoals’ lush beds of wild celery have declined with compromised water quality and increased sedimentation. Chesapeake canvasback numbers followed suit and have declined some 80 percent over the last 50 years.


Wednesday, April 17, 2013

Steller's Sea Eagle


Steller's Sea Eagle

 
Haliaeetus pelagicus

Photo: Steller's sea eagle on snow spreading wings
Holding its prey down with powerful talons, a Steller's sea eagle displays its wings, which can have a span of over 6 feet (2 meters).
Photograph by Tim Laman
These very large, powerful eagles are also striking in appearance. They are dark but dramatically colored with white tail, shoulders, rump, thighs and forehead.
These eagles are believed to breed only in far eastern Russia, along the coasts and surrounding islands of the Sea of Okhotsk and Bering Sea. They are most common on the Kamchatka Peninsula.
Each winter, many Steller's sea eagles migrate from their breeding grounds to Japan, and a few reach Korea or even farther afield. Other individuals do not migrate, but simply move to open water as winter approaches.
Open water provides these eagles with their main food sources along coastlines and lakes. In their breeding grounds, Steller's sea eagles subsist largely on salmon, and they both hunt and scavenge for this resource. Annual salmon runs provide an enormous bounty and Steller's sea eagle nests are typically located near coasts and rivers where these fish appear en masse.
These birds of prey hunt from a perch or from flight by diving and clutching prey in their talons. They also stand in shallow water or on the ice and grab passing fish when the opportunity arises. Like other eagles, Steller's also steal food from other birds.
In Japan, Steller's sea eagles feast on cod. In addition to fish, they eat crabs, shellfish, squid, small animals, ducks, gulls, and carrion.

Monday, April 8, 2013

Mallard Duck


Mallard Duck

 
Anas platyrhynchos


Photo: A mallard duck
Male mallards, or drakes, are more distinctively colored than females, who are mottled brown with a flourish of iridescent purple on their wing feathers.
Photograph by Bates Littlehales
The green head and yellow bill of the mallard duck is a familiar sight to many people living in the Northern hemisphere. In fact, the mallard is thought to be the most abundant and wide-ranging duck on Earth.
Mallards prefer calm, shallow sanctuaries, but can be found in almost any body of freshwater across Asia, Europe, and North America. They’re also found in saltwater and brackish water and are commonly found in wetlands.
The male, or drake, is the more distinctively colored of the mallards. Its iconic green head sits atop a white neckband that sets off a chestnut-colored chest and gray body. Females are mottled drab brown in color, but sport iridescent purple-blue wing feathers that are visible as a patch on their sides. They grow to about 26 inches (65 centimeters) in length and can weigh up to 3 pounds (1.4 kilograms).
Mallard groups can often be seen head dipping or completely upending in the water. They rarely dive though, spending their time near the surface and dabbling for invertebrates, fish, amphibians, and a variety of plants. They also graze on land, feeding on grains and plants.
Mated pairs migrate to and breed in the northern parts of their range and build nests on the ground or in a protected cavity. They normally lay about a dozen eggs, and the incubation period lasts just under a month. Mallards are territorial during much of this period, but once incubation is well underway, males abandon the nest and join a flock of other males.


Monday, April 1, 2013

Canada Goose


Canada Goose

 
Branta canadensis


Photo: A Canada goose watches over ten fuzzy babies as they swim
Once threatened with dwindling populations, conservation efforts have made the Canada goose very common throughout North America.
Photograph by Stephen St. John
The ubiquitous Canada goose is one of the best known birds in North America. It is found in every contiguous U.S. state and Canadian province at one time of the year or another.
Canada geese are adaptable to many habitats and may thrive wherever grasses, grains, or berries are available. Because of changing weather, settlement, and farming patterns, many Canada (not "Canadian") geese have begun to alter their migrations. Typically, the birds summered in northern North America and flew south when cold weather arrived. This cycle endures, but some northern populations have shortened their flight to traditional wintering grounds in the southern U.S. and Mexico. Other Canada geese have become permanent residents of parks, golf courses, suburban subdevelopments, and other human habitats across much of North America. In some areas, such as airports, they are so numerous that they are considered a nuisance. Just 50 geese can produce two and a half tons of excrement in a year.
When the birds do migrate, they form impressive and aerodynamic "V-formations." They can cover 1,500 miles (2,400 kilometers) in just 24 hours with a favorable wind, but typically travel at a much more leisurely rate. These noisy groups honk their way along established paths that include designated "rest stops." These social birds remain in flocks year-round, except while nesting.
Link: http://animals.nationalgeographic.com/animals/birds/canada-goose/


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