162 MIGRATION AND DISTRIBUTION 



I believe it was only some twenty or thirty years ago 

 that anything like a practical solution of the difficulty was 

 arrived at. The birds congregating about the south 

 coast are seized with a sudden impulse or mania to fly 

 upwards. This is caused by some atmospheric change 

 coinciding with a warm south wind moving in a high 

 stratum, into which the birds soar with an involuntary 

 motion of their wings. This motion (involuntary like 

 that of the heart) is continued for many hours, and the 

 birds fly blindly along until the paroxysm passes off, when 

 they at once begin to descend, making many a fatal drop 

 into the sea. 



The same phenomenon occurs in Africa and southern 

 countries, where the migratory birds congregate for a 

 northern flight about April. Experiments were tried here 

 and in Africa which tended to corroborate the above 

 facts. Migratory birds were kept in cages along the 

 coast, and it was found that each was seized with a pro- 

 longed paroxysm coinciding with the time that the wild 

 birds disappeared. Cages were constructed with silk at 

 top and bottom to prevent the birds from killing them- 

 selves ; and it was noticed that after the paroxysm had 

 passed away, the birds began to look about them, to 

 plume themselves, and eat and drink, apparently with a 

 notion that they had arrived at their new home.* 



Of this Newton writes : — 



On reading these wonderful paragraphs, some ques- 

 tions naturally arise. How does the writer account for 

 his '' birds congregating about the south coast " ? What 

 brings them there, that they may be " seized with a 

 sudden impulse or mania to fly upwards " ? Who has 

 ever observed the " atmospheric change " and coincident 

 " warm south wind moving in a high stratum " ? Do 

 these remarkable meteorological phenomena occur but 

 once in the whole season of migration, or is there a suc- 

 cession of them to suit the convenience of each migratory 

 species ? Who, moreover, has seen the birds soar into 



* Times, September 18, 1874. 



