JANUARY IN THE SUSSEX WOODS. 109 



of a kind of prehistoric memory ; sixthly, from choice. 

 One or other of these causes will explain almost every 

 case of migration. 



Birds are lively and intellectual, imaginative and 

 affectionate creatures, and all their movements are not 

 dictated by mere necessity. They love the hedge and 

 bush where they were bom, they return to the same 

 tree, or the same spot under the eave. On the other 

 hand, they like to roam about the fields and woods, 

 and some of them travel long distances during the day. 

 When the pleasurable cares of the nest are concluded, 

 it is possible that they may in some cases cross the 

 sea solely for the solace of change. Variety of food 

 is itself a great pleasure. By prehistoric memory is 

 meant the unconscious influence of ancient habit im- 

 pressed upon the race in times when the conformation 

 of land and sea and the conditions of life were 

 different. No space is left for a mysterious agency ; 

 migration is purely natural, and acts for the general 

 preservation. Try to put yourself in a bird's place, 

 and you will see that migration is very natural indeed. 

 If at some future period of the world's history men 

 should acquire the art of flying, there can be no doubt 

 that migration would become the custom, and whole 

 nations would change their localities. Man has, in- 

 deed, been always a migratory animal. History is 

 little beyond the record of migrations, how one race 

 moved on and overcame the race in front of it. In 

 ancient days lots were cast as to who should migrate, 

 and those chosen by this conscription left their homes 

 that the rest remaining might have room and food. 

 Checking the attempted migration of the Helvetii was 



