485,623 hectares (1.2 million acres) of semiarid land. Other important power
projects on the Columbia include Bonneville, The Dalles, John Day, McNary,
Priest Rapids, Rocky Reach, and Chief Joseph dams, in the United States, and
Mica Dam, in Canada. Most of these dams are also used for flood control and for
irrigation. The American explorer Robert Gray explored the mouth of the Columbia
River in 1792. He named the river for his ship. The Lewis and Clark Expedition
explored the lower Columbia from 1805 to 1806, and David Thompson, a Canadian
surveyor and explorer, followed the river from its source to its mouth in 1811.
The Columbia once had great numbers of salmon and supported a large canning
industry; the fish stock was severely depleted in the 1900s as a result of dam
construction and pollution. In an effort to protect the salmon from extinction,
the Northwest Power Planning Council in 1994 approved a plan to rebuild salmon
stock by increasing the water flow through the dams and by developing habitat
protection standards. Further Reading Continental Divide (also called the Great
Divide), ridge of mountains in North America, separating the streams that flow
west (into the Pacific Ocean) from those that flow east (into the Atlantic Ocean
and its marginal seas). Most of the divide follows the crest of the Rocky
Mountains. It extends from Alaska in the United States into the Yukon Territory
and British Columbia in Canada and forms part of the border between British
Columbia and Alberta, also in Canada. It then passes through Montana, Wyoming,
Colorado, and New Mexico in the United States and continues south into Mexico
and Central America along the crest of the Sierra Madre Occidental. The term
continental divide may be applied to the principal watershed boundary of any
continent. Fraser, river in southern British Columbia, Canada. The Fraser rises
in the Rocky Mountains, in Mount Robson Provincial Park near the Alberta border,
and flows 1370 km (850 mi) before emptying, through a delta, into the Strait of
Georgia, near Vancouver. The Fraser initially flows northwest through a section
of a deep, narrow valley called the Rocky Mountain Trench. It then turns south
near the city of Prince George, where it receives its major western tributary,
the Nechako River. In its central section, the volume of the river increases,
and below Quesnel its banks gradually take on a canyonlike aspect. Important
tributaries in this section include the West Road and Chilcotin rivers, from the
west, and the Thompson River, from the east. From Lytton to Yale the river flows
through a canyon of great scenic beauty. At the canyon’s southern end the Fraser
passes between the Cascade Range to the east and the Coast Mountains to the
west. A little below Yale, at Hope, the river turns sharply west, and the
fertile lower Fraser Valley begins. The Fraser empties into the Strait of
Georgia through three main channels. The river is used by commercial vessels for
a short distance upstream. From May to July the Fraser Valley is subject to
flooding; a series of dikes helps protect the delta. The Fraser drains an area
of about 238,000 sq km (about 91,890 sq mi). Much of the river basin is heavily
wooded, and forest-products industries dominate the economy of the settlements
along the river. The lower Fraser Valley, including the delta, has highly
productive farms. Various species of salmon spawn in the Fraser, and salmon
fisheries are located near the river’s mouth. The river has great hydroelectric
potential, but it remains undeveloped for fear of detrimental effects on the
migratory habits of the salmon. The Fraser is highly polluted, especially at its
mouth. The first European to visit the river was Sir Alexander Mackenzie in
1793. It is named for the fur trader Simon Fraser, who explored much of it in
1808. In 1858 gold was found in alluvial gravels north of Yale, and a major gold
rush ensued. Louise, Lake, glacial lake in southwestern Alberta, Canada. Lake
Louise is located at an elevation of 1731 m (5680 ft) in Banff National Park,
near the town of Lake Louise. The lake is about 2.4 km (about 1.5 mi) long and
1.2 km (0.75 mi) wide. Sheltered by the Rocky Mountains, Lake Louise is known
for the tranquil beauty of its turquoise-blue surface, which mirrors nearby
scenic forests and snowcapped peaks. The lake is fed from the north by the
spectacular Victoria Glacier and is drained by the Bow River in the southeast.
Lake Louise was named in 1884 for the Canadian governor-general’s wife, who was
also the fourth daughter of Queen Victoria. Missouri (river) (Illinois
Emissourita,"dwellers of the big muddy"), river in central United
States. The Missouri is formed by the confluence of the Jefferson, Gallatin, and
Madison rivers at Three Forks in southwestern Montana. The longest river in the
United States, the Missouri is one of the primary tributaries of the Mississippi
River. It flows 3726 km (2315 mi) and drains an area of about 1,370,000 sq km
(about 529,000 sq mi). The Missouri initially flows north, skirting the main
range of the Rocky Mountains. Then it passes through a 366-m (1200-ft) gorge
called the Gates of the Mountains, turns northeast and reaches Fort Benton,
Montana, the head of navigation. From Fort Benton the river flows east and is
joined by the Milk River at Frazer, Montana, and by the Yellowstone River at
Buford, North Dakota. From this point the Missouri flows generally southeast
through North Dakota and South Dakota to Sioux City, Iowa, where it turns south
and becomes the boundary between Nebraska and Kansas on the west and Iowa and
Missouri on the east. The Platte River is received near Omaha, Nebraska, and the
Kansas River at Kansas City, Missouri. On receiving the Kansas, the Missouri
turns east and flows across the state of Missouri. About 27 km (about 17 mi)
north of St. Louis, the muddy Missouri enters the channel of the Mississippi.
Other important cities on the river are Bismarck, North Dakota; Council Bluffs,
Iowa; Saint Joseph, Missouri; and Atchison, Leavenworth, and Kansas City,
Kansas. The upper Missouri traverses mountainous terrain covered with dense
coniferous forests. These forests support large animals, including bears, elk,
and moose. Fish found in the cold upper river include the Montana grayling and
the rainbow trout. The middle and lower river valleys are lined with grasslands
and forests of poplar, hickory, and other trees, providing a habitat for
rabbits, foxes, beavers, and other animals. Fish in the warmer lower river
include bass, several species of catfish, and carp. Historically, a number of
Native American peoples lived in the valley along the Missouri, including the
Hidatsa, Crow, Iowa, Arikara, Blackfoot, and Sioux. The region was popular for
buffalo hunting and agriculture, and the tribes used the river for commerce. In
1673 French-Canadian explorer Louis Jolliet and French missionary and explorer
Jacques Marquette became the first Europeans to discover the Missouri when they
came across the lower river during a journey down the Mississippi. The lower
river became an important route for fur traders, who began to venture farther up
the river. During the Lewis and Clark Expedition of 1804 to 1806, American
explorers Meriwether Lewis and William Clark became the first whites to explore
the river basin from its mouth to its headwaters. Steamboat traffic on the
Missouri began in 1819 with the voyage of the Independence, and soon steamboats
were taking settlers west, as well as hauling freight such as grain, fur,
lumber, and coal. Steamboat activity peaked in 1858, but then the construction
of railroads lessened traffic on the river. The lower portion of the river now
supports commercial barge lines, which carry agricultural products, steel, and
oil. In order to enhance navigability and provide flood control, hydroelectric
power, and irrigation, the Missouri River Basin Program was created in 1944.
Under this program and the subsequent Missouri Basin Program, a series of dams,
reservoirs, and locks were built on the river. However, in 1993 heavy rains
caused record-breaking flooding along the Missouri and other branches of the
Mississippi River. Further Reading Saskatchewan (river, Canada), river in
central Canada, 550 km (340 mi) long. It is formed in central Saskatchewan by
the confluence of the North Saskatchewan and South Saskatchewan rivers and flows
east into Manitoba, where it passes through Cedar Lake before emptying into Lake
Winnipeg. The North Saskatchewan River (1200 km/760 mi long) rises in the Rocky
Mountains of southwestern Alberta and flows east past Edmonton, Alberta, and
Prince Albert, Saskatchewan. The South Saskatchewan River (1390 km/865 mi long),
formed by the juncture of the Bow and Oldman rivers in southern Alberta, flows
northeast past Medicine Hat, Alberta, and Saskatoon, Saskatchewan. The
Saskatchewan River system stretches 2600 km (1600 mi) and drains most of the
western prairie. It was an important route in the fur trade of the 18th century
but has no navigational value today. The river system is widely used for
irrigation, however, and it has several hydroelectric facilities, notably
Gardiner Dam on the South Saskatchewan River, near Saskatoon, and Grand Rapids
Dam, at the mouth of the Saskatchewan River. Arapahoe Peak, mountain, northern
Colorado, in the Front Range of the Rocky Mountains, near Boulder; 4117 m
(13,506 ft) high. On the face of the peak is an ice field known as Arapahoe
Glacier. Blanca Peak, mountain, south central Colorado, in the Sangre de Cristo
Range of the Rocky Mountains, near Great Sand Dunes National Monument. It is
4372 m (14,345 ft) high and is one of the highest mountains in the state. Pikes
Peak, one of the most famous peaks in the Rocky Mountains, located in the Front
Range, central Colorado, near Colorado Springs. Although the elevation (4301
m/14,110 ft) of the peak is not the highest in the state, Pikes Peak is noted
for a commanding view. Tourists can ascend the mountain by three different
means: by horseback, by a cog railway approximately 14 km (9 mi) long, or by
automobile over a well-constructed road. Two springs, Manitou and Colorado, are
located near the foot of the mountain. On the summit of Pikes Peak is a
meteorological station. The peak was discovered in 1806 by the American explorer
and army officer Zebulon Montgomery Pike. It was first climbed in 1820.
Bufflehead, common name for a small north American diving duck. Its name is
derived from "buffalo-head," an allusion to the large size of its
short-billed head, especially in males, created by especially puffy feathers.
The body plumage of males is black and white above and white below, the head
glossy black with a large white patch from the eye to the back edge. Females are
dark brown, with a smaller white patch on the side of the head. Adults are about
38 cm (about 15 in) long. Buffleheads nest in wooded areas of Canada and the
Rocky Mountains, and winter on bays, lakes, rivers, and harbors. Scientific
classification: The bufflehead belongs to the tribe Mergini in the family
Anatidae. It is classified as Bucephala albeola. Grosbeak, common name for
several species of large-billed seed-eating birds of the fringillid, or finch,
family and of the emberizid family. Of the fringillid grosbeaks, only two are
found in North America: the relatively small billed pine grosbeak, of northern
coniferous forests around the world, and the very large billed evening grosbeak.
The latter species breeds in coniferous forests in Canada and the northernmost
United States, extending in the Rocky Mountains south to Mexico. It winters
irregularly in the United States, in some years invading in great numbers,
occasionally south to northern Florida. Until the 1950s it bred only as Far East
as Michigan and Ontario, but it then began expanding its range to New York, New
England, and the Maritime Provinces. Some attribute this expansion to better
winter survival, as many people put out sunflower seeds and other food for these
birds. Some cardinaline grosbeaks are entirely tropical. In North America the
best-known species are the rose-breasted grosbeak, of the east, and its western
counterpart, the black-headed grosbeak. In both the male is strikingly colored:
black and white with a bright-pink breast spot in the former, and black and
orange-brown in the latter. The females look like giant sparrows. The blue
grosbeak is found in the southern United States and Mexico. Males are rich blue
with brown wing bars, and females are dark brown. Scientific classification:
Grosbeaks belong to the families Fringillidae and Emberizidae, of the order
Passeriformes. They are sometimes all placed in either one of those families.
The pine grosbeak is classified as Pinicola enucleator, the evening grosbeak as
Coccothraustes vespertina (sometimes Hesperiphona vespertina), the rose-breasted
grosbeak as Pheucticus ludovicianus, the black-headed grosbeak as Pheucticus
melanocephalus, and the blue grosbeak as Guiraca caerulea. Grouse, common name
for 17 species of birds of the pheasant family, found around the world in the
northern hemisphere; two of the three species of ptarmigan inhabit both the
Americas and Eurasia. Grouse vary in size from males of the capercaillie, 86 cm
(34 in) long, of European coniferous forests, to the 32 cm (12.5 in)
white-tailed ptarmigan, of western North American Mountains. In most species the
sexes differ in color, but none have truly bright plumage. Bright colors are
limited to red or yellow comblike structures over the eyes, expanded during the
breeding season, or sacs of naked skin that inflate like balloons during
courtship displays. Mating systems are elaborate in most grouse, and in many the
males are polygamous, meeting in the spring at certain arenas where they compete
for mates. As highly popular game birds, grouse have been intensively studied.
Best known and most widely distributed of the American species is the ruffed
grouse, which occurs in woodlands from Alaska to Newfoundland, south to the
northern Rocky Mountains and the Appalachians. The name comes from a ruff of
black (rarely, coppery) feathers at the sides of the neck. These feathers are
larger in males than in females, and are spread widely during courtship
displays, when the male struts on a moss-covered log. This species is famous for
the springtime "drumming" of the males, a sound produced by the
beating of the wings against the air, as the male stands erect. The sound
carries a great distance, and resembles a noisy gasoline engine starting up. Two
other North American grouse, the blue grouse of western mountains and the more
widely distributed spruce grouse are confined to coniferous forests. The male
blue grouse has inflatable neck sacs, varying geographically in color from
yellow to reddish purple; the spruce grouse lacks such sacs. These two species
have been called "fool hens" because of their apparent fearlessness,
making them easy to hunt. Two species of prairie chicken, the closely related
sharp-tailed grouse, and the sage grouse, dwell in open country. The latter, an
inhabitant of sagebrush areas, especially in the Great Basin, is the largest
American grouse. Males reach 75 cm (30 in) in length; females are smaller (58
cm/23 in). During the communal courtship displays, males strut about with their
spiky tail feathers fanned out, and a pair of yellow sacs on their chests
inflated. Scientific classification: Grouse belong to the family Phasianidae of
the order Galliformes. The capercaillie is classified as Tetrao urogallus, the
white-tailed ptarmigan as Lagopus leucurus, and the ruffed grouse as Bonasa
umbellus. The blue grouse is classified as Dendragapus obscurus and the spruce
grouse as Dendragapus canadensis. Prairie chickens are classified in the genus
Tympanuchus. The sharp-tailed grouse is classified as Tympanuchus phasianellus
and the sage grouse as Centrocercus urophasianus. Further Reading Solitaire
(bird), common name applied to various species of American thrush. In the United
States, one species, Townsend’s solitaire, is found chiefly in the Rocky
Mountains. The bird is largely brownish gray in color, with a white-eye ring and
a buff wing patch. All solitaires are superb singers. Solitaire was also the
name of an extinct, flightless bird resembling the dodo. It inhabited Rodrigues,