FIELD SPORTS RELATED TO NAT. HIST. 15 



enough to follow the life of the May-fly, but 

 I shall willingly have my attention directed 

 to its habits. Indeed, I have often regretted 

 that sportsmen were not fonder of zoology; 

 they have so many opportunities, which other 

 persons do not possess, of illustrating the 

 origin and qualities of some of the most cu- 

 rious forms of animated nature ; the causes 

 and character of the migrations of animals ; 

 their relations to each other, and their place 

 and order in the general scheme of the uni- 

 verse. It has always appeared to me, that 

 the two great sources of change of place of 

 animals, was the providing of food for them- 

 selves, and resting places and food for their 

 young. The great supposed migrations of 

 herrings from the poles to the temperate 

 zone, have appeared to me to be only the 

 approach of successive shoals from deep to 

 shallow water, for the purpose of spawning. 

 The migrations of salmon and trout are evi- 

 dently for the purpose of depositing their ova, 

 or of finding food after they have spawned. 

 Swallows, and bee-eaters, decidedly pur- 

 sue flies over half a continent ; the scolo- 



