ANIMAL FLIGHT lOQ 



to the southward, and other birds from the north, like the 

 northern chickadees and nuthatches, the crossbills, and the 

 pine and evening grosbeaks, appear in the places they have left. 

 Some birds, like the robin, do not go very far, wintering chiefly 

 in the southern states. Many go to Central and South Amer- 

 ica, while a few travel enormous distances. The Golden Plover, 

 which nests in the extreme north of North America, winters 

 in the south of South America. This bird after leaving Lab- 

 rador ordinarily does not come down again until it arrives in 

 Guiana, more than 1700 miles away. It is frequently seen 

 passing over the easternmost of the West Indies at an immense 

 height, and has also been seen high in air several hundred miles 

 east of the Bermudas. Coming north it takes a different route, 

 up the Mississippi valley. The Eastern Godwit, a plover-like 

 bird which nests in Alaska and in eastern Siberia, spends the 

 winter in New Zealand. A great many apparently feeble birds 

 can cover enormous distances without alighting. The little 

 Sora rail can cross the Caribbean Sea twice a year without 

 difficulty, and two sorts of cuckoos pass every year from New 

 Zealand to New Caledonia and back over 1000 miles of sea. 

 In many places it is still erroneously believed that the small 

 birds get about by simply perching on the backs of larger birds 

 and being carried by them, so incredible do such powers of flight 

 appear in such weak creatures. 



The height at which birds migrate varies considerably. 

 From measurements taken on birds as they crossed the face of 

 the moon at night it w^as found that the migrations in May 

 were at a height of from 1200 to 2400 feet, and those in Octo- 

 ber at between 1400 and 5400 feet. 



The flight of birds may be roughly divided into three types, 

 ordinary flight, with almost innumerable variations, such as we 

 see in the common land birds, soaring, and gliding. In the usual 

 type of flight the bird moves through the air with a continual 

 motion of the wings. This is the only type of flight possible in 

 still air, and is characteristic of most land birds, ah the smaller 

 sea birds, the ducks, geese, herons, and many others. 



