Tundra swan :: essays research papers

TUNDRA SWAN The Tundra Swan is the most widespread and numerous species of swan in North America. Though the Tundra Swan is mostly found in Alaska or Canada, many flocks are now beign spoted in Oregon. Tundra swans, once called whistlers, are winter visitors to Oregon. More and more are now seen in the Willamette Valley and along the Columbia River northwest of Portland. With a wingspread to about 7 feet, males weigh around 20 lbs. Tundras vary in size from 4 to 4 1/2 ft. long. Females are slightly smaller than males. Sometimes tundras are mistaken for snow geese which are much smaller birds with black wing tips. You can certainly tell a Tundra Swan from their bill. It is all black bill with variably-sized yellow spot at base. Some swans have short, duck-like bills... but the Tundra Swan has a long, strait bill. Imature Tundra Swans have a body much grayer than an adult. Males are called cobs while females are called pens. When nesting, Swans gather and pile up grass and mosses within 100 yards of water. The resulting nest measures about 6 feet across and 12-18 inches high. This nest will support the eggs above water level and provide a lookout station for the swans to guard against predators. During incubation, females care for the eggs while their mates stand guard nearby. The female does most of the incubation, but the male will sit on the nest while she eats. The nest varies from 2-8 rough shelled, pale yellow or creamy/ white eggs which hatch in late June. When the downy, ash-gray chicks emerge... they weigh about 180 g. They are soon able to forage for themselves. Both parents help them find suitable plant food around the peramiters of the nest. The young enter the water soon after hatching. Food for the tundra swans is largely vegetative. Their long necks equip them to reach bulbous roots which they dislodge with their feet from the bottom of the shallow ponds. Occasionally they will feed on farm crops. While wintering on the east coast, they also feed on mollusks and crustaceans. While the flock is feeding one swan stands guard to warn of any approaching danger. To achieve flight, swans face the wind, run along the surface of water for 15 to 20 feet, flap their wings, and beat the water with their feet alternately until they have gained sufficient headway to launch into the air.