82 Retrospective Criticism. 



migration; a return and departure which seldom exceed, 

 from year to year, and at great intervals, more than a few days. 

 Then comes the query, whence the cause? Which is an- 

 swered compendiously, by repeating the term instinct. In 

 this case, instinct acts by wholesale and retail. Some birds 

 pass from the river to the lake, from the land to the moor, 

 from the plain to the mountain. Some cross the narrow 

 seas, others despatch the broad deep and continents in their 

 transit. Some birds assemble in bodies, and seem to hold 

 aggregate meetings to counsel respecting their departure ; 

 while other birds escape individually, as if any notice of their 

 intent might subject them to a ne exeat regno [a forbidding to 

 leave the kingdom]. For men to call all these movements in- 

 stinct, is to give a name to ignorance, and to take credit for 

 their philosophy when they discredit themselves. A change of 

 local position is also common to many of the four-footed 

 race. The passage of pigeons, mentioned by Bruce in Egypt, 

 is not more certain than that of deer in the polar regions ; and 

 M'Gregor mentions the remains of approaching fences 

 of many miles' length, in Nova Scotia, by the Acadians, to 

 bring the moving herds within a narrow pass, to be taken 

 or killed. Birds and beasts, and fishes, for they journey to 

 and fro in the ocean, as their fellows of the air and earth 

 tread or wing their way, are moved by the temperature of 

 the element of their existence, and the means of their feeding. 

 These often rule the migration of cattle in their artificial 

 state. Hill and valley are not more certainly interchanged 

 than the sheep in Spain are driven north and south as the 

 year changes, and as the herbage, in -consequence, is scanty 

 or plentiful. Breeding of the racer is not a predisposing 

 cause ; it may be an accident or not. The Esquimaux shift 

 their position for the convenience of food only, and these 

 are kindred with lower animals. When men use the word 

 instinct, they use it for the most part in contradistinction to 

 reason. Yet reason, or that which regulates man's motions, 

 is often the arbiter of the progress of birds. Men in the 

 infancy of navigation crept along the shore, or navigated from 

 headland to headland; or, in crossing, chose the narrow 

 passes, and those which were assisted by intervening islands. 

 Birds of passage adopt all these facilities. The birds which 

 migrate from Scotland to Ireland, proceed by the Straits of 

 Portpatrick ; and the flights of larks, lapwings, starlings, &c, 

 by this track are enormous. Besides, it has been observed, 

 that these birds begin with the morning, and wait for a side 

 wind. The same is observable in other parts of the world. 

 They seize the smallest advantage, and Capri has been in all 



