56 THE BOOK OF MIGRATORY BIRDS 



represented by the mere isolated remnants of what, in 

 primary geological periods, were large land connections 

 between different continents. 



In the case of birds crossing over from America to 

 Europe, such a connection is assumed to be formed by 

 Greenland, Iceland, the Faroes, Shetland and Orkney 

 Islands. The employment of this path as a migration 

 route is considered to have developed into a habit, and 

 this habit to have passed by hereditary transmission from 

 one generation to another from primitive times down to the 

 present day, so that the birds now in existence are able to 

 find their way with perfect certainty from one to another 

 of these mutilated remnants of a previously continuous 

 chain of land in spite of the fact that these detached frag- 

 ments lie far beyond their range of vision. 



Italy, which at one time connected Europe with Africa, 

 dividing the Mediterranean into two inland lakes, is said 

 to have formed a land bridge of this kind for birds 

 exchanging their habitations between these two continents. 



As to the arrival and departure of our friends the 

 migrants, I am at one with an eminent practical fowler, 

 who, in his writings, talks as one who has well studied his 

 subject. I refer to Mr. Stanley Duncan, of Hull, and I 

 cannot do better than to copy, with his kind permission, 

 his remarks as follow : 



"Some notes relative to the dates on which numbers of 

 our shore-birds and wild fowl visit or reach our shores 

 from their breeding homes and northern haunts may here 

 be very fitting. 



Several species of shore-birds and wild fowl breed in 

 our islands, but their numbers (even if all stayed the year 

 round), are very small compared with those which reach 

 us from the north. What are known as residential birds, 

 such as the redshank, curlew, green plover, golden plover, 

 dunlin, mallard, and teal, by the end of July begin to flock 

 on the coast, either from our local breeding-grounds or 

 from those abroad. In August most of the curlew and 

 golden plover have left their moorland haunts and resorted 



