192 THE MIGRATION OF BIRDS. 



West than in the East. Thus, for instance, while 

 we find many Ducks and Geese wintering off the 

 coasts of Scandinavia, and even in the Baltic on the 

 Adantic sea-board of Europe, but few, if any, 

 frequent Lake Baikal, the seas round Kamtschatka 

 or the Sea of Ochotsk, situated in precisely similar 

 latitudes in Central Asia and on the Pacific sea- 

 board of that continent. The aquatic zone of East 

 Palasarctic birds may be said to be the lakes and 

 great rivers of India and China, the northern portions 

 of the Indian Ocean, and the China, Yellow, and 

 Japan Seas. For the same great climatal reasons — 

 the East Palaearctic region being so much colder 

 than the West — the winter zones of land birds not 

 only do not commence so far north, but extend 

 many degrees further south than South Africa, into 

 Australia and New Zealand. The northern winter 

 zone may be said to include Turkestan, Afghanistan, 

 India, Burma, the Siamese Peninsula, South China, 

 and the south island of Japan. A comparison of 

 the winter range of some extreme eastern Palas- 

 arctic species with that of others in the extreme 

 west, affords interesting evidence of the great influ- 

 ence exerted by the Gulf Stream on the migration 

 of birds. Take, for example, the Redwing {Tiirdus 

 i/iacus), breeding in Scandinavia, say in lat. 6^°, and 

 wintering in the British Islands only ten degrees 

 further south, and compare it with the Dusky 

 Ouzel {Merula fuscata), breeding in a similar 

 latitude in Eastern Siberia (lat. 6^°), but wintering 

 in China and Japan, more than looo miles further 



