FIELD SPORTS RELATED TO NAT. HIST. 15 



change of place of animals, was the providing 

 of food for themselves, 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 evidently for the purpose of deposit- 

 ing their ova, or of finding food after they 

 have spawned. Swallows, and bee-eaters, de- 

 cidedly pursue flies over half the globe ; the 

 scolopax or snipe tribe, in like manner, search 

 for worms and larvae, flyingfrom those coun- 

 tries where either frost or dryness prevents 

 them from boring, making generally small 

 flights at a time, and resting on their travels 

 where they find food. And a journey from 

 England to Africa is no more for an animal 

 that can fly, with the wind, one hundred miles 

 in an hour, than a journey for a Londoner to 

 his seat in a distant province. And the mi- 

 grations of smaller fishes or birds always oc- 

 casion the migration of larger ones, that prey 

 on them. Thus, the seal follows the salmon, 



