94 THE MIGRATION OF BIRDS. 



of the Straits of Gibraltar, the Balearic Isles, 

 Sardinia, and Sicily ; those from Eastern Europe 

 by way of the Greek Archipelago and Candia, the 

 Black Sea and Cyprus. There is also a very 

 considerable amount of migration across the North 

 Sea, which is the route chosen by many birds on 

 their way from Scandinavia to the British Islands, 

 crossing from the Dovre^eld in Norway to the 

 Shetlands, where the water passage is not more than 

 a couple of hundred miles. Birds either come by 

 this route to our islands, either to winter or to pass 

 still further south ; or follow the continental land 

 and cross by way of Heligoland and the Straits of 

 Dover. A very important stream of migration 

 also crosses this sea nearly due east and west, but 

 there is little or no evidence to show that the 

 passage is made across the widest part. It is very 

 significant how few Palccarctic birds extend their 

 migrations to New Zealand, compared with the 

 number that regularly visit Australia, South Africa, 

 or South America. New Zealand is so remarkably 

 isolated that an ocean flight of upwards of 700 

 miles without a break of any kind is necessary to 

 reach it. Of the great number of migratory birds 

 that leave the east Palaearctic region and China in 

 autumn to winter in the Malay Archipelago, New 

 Guinea, and Australia (across seas thickly studded 

 with islands), scarcely any extend their migration 

 to New Zealand, either wisely declining the long 

 continuous ocean passage, or totally ignorant of 

 that country's existence. 



