298 THE BIOLOGY OF THE SEASONS 



civilised men, like the hero of Du Manner's Martian, who 

 always knew where the North Pole was, when he was in 

 good health at least. 



The " homing " of pigeons is very suggestive in this 

 connection. They may be transported in a basket by train 

 or steamer and set free many miles from their dovecot 

 and they are usually soon home. According to Tegetmeier, 

 an acknowledged authority, the power is mainly the out- 

 come of great sensory acuteness, and requires training if 

 the birds are to excel. 



Professor Newton spoke of the migration of birds as 

 " perhaps the greatest mystery which the whole animal 

 kingdom presents a mystery which attracted the attention 

 of the earliest writers, and can in its chief point be no more 

 explained by the modern man of science than by the simple- 

 minded savage or the poet or prophet of antiquity." But 

 this was perhaps too pessimistic. Admitting that " our 

 ignorance is still immense," may we recognise some hints of 

 progress towards greater clearness. We are slowly learning 

 to sift our data and to put our questions in more useful 

 form. Three methods have been followed with much 

 success. The first, associated especially with the name 

 of Gatke of Heligoland, is that of registering the arrivals 

 and departures of birds on a small area that can be 

 thoroughly explored. The second, associated especially 

 with the name of Eagle Clarke of Edinburgh, is that of 

 collecting data from lighthouses and lightships and similar 

 strategic points as to the annual streams of migrants. The 

 third, associated especially with the name of Thienemann 

 of Rossitten, is that of marking birds with numbered 

 aluminium rings and registering the whereabouts of those 

 (a small percentage) that are heard of again. 



