120 



be no such thing as landmarks, but with older individuals we can 

 imagine that while this sense of directioi> enables them to land on 

 a particular stretch of coast, perhaps at the mouth of a river, 

 whose course they follow, it is by power of memory, aided by 

 familiar landmarks, that they eventually reach the desired goal. 

 These latter portions of the flight are no doubt conducted in short 

 stages and during the hours of daylight. Travellers in northern 

 countries make little or no reference to migration by night, though 

 this is so great a feature of the movement in temperate regions. 

 The concluding portions of these journeys may thus traverse 

 very circuitous routes. Observations conducted by the writer in 

 a limited locality have proved beyond a doubt that certain species 

 reach their breeding grounds from a direction entirely opposite to 

 that which might have been expected, from our knowledge of the 

 general trend of the spring flight. Moreover, other species at 

 the same time cross this flight at an acute angle in travelling to 

 districts further removed. 



It will not be uninteresting at this stage of the argument to 

 follow in imagination, the migratory flight of a flock of birds, 

 conducted in the normal manner, according to the theories of 

 Herr Gatke, from their breeding grounds in the north-east to 

 their winter quarters in the west or south-west of Europe. Let 

 us suppose that we are dealing with one of the " many hun- 

 dreds " which pass Heligoland on their journeys from "fax 

 eastern Asia." 



It is dusk — and the time for departure has arrived. Without 

 more flocking together than has accidentally taken place during 

 feeding time, all the residents in a particular area set out from 

 their breeding grounds on a journey of two thousand miles or 

 more. No food has been taken for some hours, and the winds 

 being unfavourable near the surface of the earth, all rise to a 

 height of at least 20,000 feet, whence guided by some unknown 

 power, and at a speed of from 150 to 200 miles an hour, they set 

 out on their rushing and undeviating flight to the west of Europe. 

 Here, however, the direction of the latter must be altered and a 

 turn to the south executed in mid-air, which carries them, after a 

 further flight, to the neighbourhood of Heligoland, where again a 

 second turn is accomplished and the remainder of the journey is 



