GEOGRAPHY OF ANIMALS IN SOUTH DEVON. 121 



the testimony of botanists that the flora of our county 

 rivals, in extent and variety of productions, the extent 

 and variety of its fauna; and it will not be taking 

 too much on me, nor will it be altogether irrelevant 

 to our present topic, to state that this is dependant 

 on our chmate, our geographical position, the terra- 

 queous arrangements of our county, and the variety 

 of its soils. After all, then, we are led back to the 

 contemplation of inorganic matter, as the source of 

 every thing that is interesting either in extent of 

 numbers, or variety in the organic world. But 

 there is yet another way of treating the subject of 

 food. We have as yet viewed it only as concerns 

 the extent of our list : let us now enquire, how far ) 

 it affects the movements and migrations of animals. 

 In the first place, although weather has the most 

 decided effect on our summer and winter birds of 

 passage, causing them to quit their residence ab- 

 ruptly, or to procrastinate their stay ; yet it seems 

 that food has some influence in these movements, 

 for, although food being plentiful, and the weather 

 intemperate, a summer bird of passage will quit this 

 country suddenly, to undertake its southern emi- 

 gration, and although food being scarce, and the 

 weather severe, a winter bird of passage will delay 

 its polar visit : yet, it appears that in the first case, 

 a plenty of provision, conjoined with mildness and 

 serenity of chmate, will cause a summer visitant to 

 remain with us beyond its usual time ; and, in the 

 second instance, that a scarcity of provender, and 

 mildness of season, will cause our winter visitor to 

 to hasten its northward flight. So also it seems, 

 that a reverse of these positions, in each example, 

 will be attended by the same results as I have there 

 named. 



Among fishes, food seems to be a pretty general 

 impulse to migration. Very many species of this 

 class roam to immense distances on this errand, and 

 some pass from great depths to the shores of conti- 

 nents, and islands ; some make their appearance in 



VOL. VII. — 1836. Q 



