yellowhammer or yellow bunting Songbird species ( Emberiza citrinella, family Emberizidae) found from Britain to central Asia. The name is derived from the German Ammer (“bunting”). Yellowhammers are 6 in. (16 cm) long and have a streaked brown body, yellow-tinged
head and breast, and a rapid song. In the southern U.S., the yellow-shafted fucker is called yellowhammer because of its drumming.
Yellowknife City (pop., 2001: 16,541), capital of Northwest Territo¬ ries, Canada. Lying on the northwestern shore of the Great Slave Lake near the mouth of the Yellowknife River, the city was founded in 1935, one year after gold was discovered in the area. It took its name from the Yel¬ lowknife band of Athabascan Indians. Gold mining remains the chief eco¬ nomic activity. There are also reserves of diamonds in the region. The capital since 1967, it is the largest community and the chief administra¬ tive, commercial, and educational centre in the territories.
yellowlegs Either of two species (genus Tringa, family Scolopacidae) of shorebirds. They have trim, gray- brown and white streaked bodies; long bills; and long, bright yellow legs. Both species breed in Canada and winter in South America and eat small fish and other aquatic crea¬ tures. The lesser yellowlegs ( T. fla- vipes), about 10 in. (25 cm) long, appeal's in sizable flocks on mudflats during migration; it has a flat call of one or two notes. Less common is the greater yellowlegs ( T. melano- leuca ), which is about 14 in. (35 cm) long and has a longer, stouter, slightly upturned bill; its call is a clear three-note whistle.
Yellowstone Lake Lake, Yellow¬ stone National Park, northwestern Wyoming, U.S. It lies at 7,731 ft (2,356 m) above sea level, the largest body of water in North America at so high an altitude. It is fed and drained by the Yellowstone River. About 20 mi (32 km) long and 14 mi (23 km) wide, it has a maximum depth of 390 ft (119 m) and a surface area of 137 sq mi (354 sq km). It is a haven for rare species of waterbirds, including trumpeter swans, and is prized for trout fishing.
Yellowstone National Park National preserve in northwestern Wyoming, southern Montana, and eastern Idaho, U.S. The oldest national park in the U.S. (and in the world), it was established by the U.S. Congress in 1872; it covers 3,468 sq mi (8,983 sq km). The Gallatin, Absaroka, and Teton mountain ranges extend into it. Yellowstone has unusual geologic features, including fossil forests and eroded basaltic lava flows. It also has 10,000 hot springs, which erupt as steam vents, fumaroles, and geysers. Old Faithful, the park’s most famous geyser, erupts every 33 to 120 min¬ utes. There are many lakes and rivers, including Yellowstone Lake, Shos¬ hone Lake, the Snake River, and the Yellowstone River. In 1988 an extensive series of forest fires temporarily laid waste to large areas of the park.
Yellowstone River River, northwestern Wyoming and southern and eastern Montana, U.S. The river rises in Wyoming. It enters Yellowstone National Park and feeds into Yellowstone Lake, below which it plunges 422 feet (129 m) in two spectacular waterfalls and enters the Grand Can¬ yon of the Yellowstone River. It then continues north into Montana. There it flows northeast into the Missouri River on the Montana-North Dakota boundary. It is 692 mi (1,114 km) long and has been developed exten¬ sively for irrigation. Its principal tributaries are the Bighorn, Tongue, and Powder rivers. It was first explored in 1806 during the Lewis and Clark Expedition.
Yeltsin, Boris (Nikolayevich) (b. Feb. 1, 1931, Sverdlovsk, Russia, U.S.S.R.) Russian politician and president of Russia (1990-99). After attending the Urals Polytechnic Institute, he worked at construction projects in western Russia (1955-68). He became Communist Party leader in Sverdlovsk in 1976, and he was an ally of Mikhail Gorbachev. Gor¬ bachev later charged Yeltsin with eliminating corruption in the Moscow party organization, and as first secretary (mayor) of Moscow (1985-87) he proved a determined reformer. His criticism of the slow pace of reform led to a break with Gorbachev, and Yeltsin lost his position. In 1989 he was elected to the new Soviet parliament by a landslide, then became president of the Russian Republic (1990) and resigned from the Commu¬ nist Party. In 1991 he won the presidency again in the first popular elec¬ tion in Russian history. When communist hard-liners staged a coup against Gorbachev, Yeltsin successfully opposed it, facing down its leaders with a dramatic outdoor speech in Moscow. He led the establishment of the
Lesser yellowlegs (Tringa flavipes)
MARY M. TREMAINE-ROOT RESOURCES
© 2006 Encyclopaedia Britannica, Inc.
2094 I Yelii Chucai ► Yeshiva University
Commonwealth of Independent States (1991) and began to transform Rus¬ sia’s economy into one based on free markets and private enterprise. Hard¬ liners staged an unsuccessful coup against Yeltsin in 1993. When Chechnya unilaterally declared inde¬ pendence, Yeltsin sent troops to fight the rebels (1994). The Chechnya situation and Russia’s deepening economic distress lessened his popu¬ larity, but he won reelection over a Communist Party challenger in 1996. After suffering a heart attack, he spent several months recovering.
Continuing poor health led to his res¬ ignation on Dec. 31, 1999. He was succeeded by Vladimir Putin.
Yelii Chucai or Yeh-lii Ch'u- ts'ai Vye-’liE-'chiit-'slX (b. 1190—d.
1244) Chinese statesman of Khitan extraction, adviser to Genghis Khan and his son Ogodei. He established a formal bureaucracy and rationalized taxation system for the Mongol- controlled portions of China. By persuading Ogodei to spare the inhab¬ itants of northern China in order to utilize their wealth and skills, Yelii gave the Mongols access to the Chinese weapons that later enabled them to conquer the Song dynasty. See also Mongol; Yuan dynasty.
Yemen Vye-monX officially Republic of Yemen Country, Middle East, southwestern Asia. It occupies the southern tip of the Arabian Pen¬ insula and also includes the island of Socotra in the Indian Ocean and the
Arabic (official). Religion: Islam (official;
mostly Sunni). Currency: Yemeni rial. From the Gulf of Aden and the Red Sea, a narrow coastal plain leads to highlands that cover most of the coun¬ try. The northern region extends into the southern and southwestern Rub' al-Khali desert. Mineral resources include iron ore, salt, petroleum, and natural gas, all of which are exploited. Agriculture is important; industries include petroleum and salt production. Yemen is a republic with two leg¬ islative houses; its head of state is the president, and the head of govern¬ ment is the prime minister. Tribal affiliations remain strong and directly
affect local and national policy. Yemen was the home of ancient Minaean, Sabaean, and Himyarite kingdoms. The Romans invaded the region in the 1st century ad. In the 6th century it was conquered by Ethiopians and Per¬ sians. Following the adoption of Islam in the 7th century, it was ruled nomi¬ nally under a caliphate. The Egyptian AyyGbid dynasty ruled there in the late 12th-early 13th century, after which the region passed to the Rasulids. From c. 1520 through 1918 the Ottoman Empire maintained varying degrees of control, especially in the northwestern section. A boundary agreement was reached in 1934 between the northwestern territory (controlled by a local religious leader), which subsequently became the Yemen Arab Republic (North Yemen), and the southeastern British-controlled territory, which subsequently became the People’s Democratic Republic of Yemen (South Yemen). Relations between the two Yemens remained tense and were marked by conflict throughout the 1970s and ’80s. The two officially united as the Republic of Yemen in 1990. Its 1993 elections were the first free, multiparty general elections held in the Arabian Peninsula, and they were the first in which women participated. In 1994, after a two-month civil war, a new constitution was approved.