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The sandhill crane (''Grus canadensis'') is a species of large crane of North America and extreme northeastern Siberia. The common name of this bird refers to habitat like that at the Platte River, on the edge of Nebraska's Sandhills on the American Plains. This is the most important stopover area for the nominotypical subspecies, the lesser sandhill crane (''Grus canadensis canadensis''), with up to 450,000 of these birds migrating through annually. ==Description== Adults are gray overall; during breeding, their plumage is usually much worn and stained, particularly in the migratory populations, and looks nearly ochre. The average weight of the larger males is , while the average weight of females is , with a range of across the subspecies.〔(Sandhill Crane. Appendix 2 ). The Birds of North America. bna.birds.cornell.edu〕〔 Sandhill cranes have red foreheads, white cheeks, and long, dark, pointed bills. In flight, their long, dark legs trail behind, and their long necks keep straight. Immature birds have reddish-brown upperparts and gray underparts.〔(Sandhill Crane ). Allaboutbirds.org. Retrieved on 2012-12-30.〕〔(Sandhill Crane ). Seattleaudubon.org. Retrieved on 2012-12-30.〕 The sexes look alike. Sizes vary among the different subspecies; the average height of these birds is around .〔(Sandhill Crane ), International Crane Foundation〕〔Dunn, J.L. & Alderfer, J., editors. Field Guide to the Birds of North America. National Geographic, Washington, D.C.〕 Their wing chords are typically , tails are , the exposed culmens are long, and the tarsi measure .〔Johnsgard, Paul A. (1983). (Cranes of the World: Sandhill Crane (''Grus canadensis'') ). University of Nebraska-Lincoln〕 These cranes frequently give a loud, trumpeting call that suggests a rolled "r" in the throat, and they can be heard from a long distance. Mated pairs of cranes engage in "unison calling". The cranes stand close together, calling in a synchronized and complex duet. The female makes two calls for every one from the male. Sandhill cranes' large wingspans, typically , make them very skilled soaring birds, similar in style to hawks and eagles.〔 Using thermals to obtain lift, they can stay aloft for many hours, requiring only occasional flapping of their wings and consequently expending little energy. Migratory flocks contain hundreds of birds, and can create clear outlines of the normally invisible rising columns of air (thermals) they ride. Sandhill cranes fly south for the winter. In their wintering areas, they form flocks over 10,000. One place this happens is at Bosque del Apache National Wildlife Refuge, south of Albuquerque, New Mexico. An annual Sandhill Crane Festival is held there in November. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sandhill crane」の詳細全文を読む スポンサード リンク
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