APPENDIX. 357 



problem have often been confused together under the word 

 instinct* With respect to the period of starting, it cannot 

 of course be memory in the young cuckoos' start for the first 

 time two months after their parents have departed : yet it 

 deserves notice that animals somehow acquire a surprisingly 

 accurate idea of time. A. d'Orbigny shows that a lame 

 hawk in S. America knew the period of three weeks, and 

 used at this interval to visit monasteries when food was dis- 

 tributed to the poor. Difficult though it may be to conceive 

 how animals either intelligently or instinctively come to 

 know a given period, yet we shall immediately see that in 

 some cases our domestic animals have acquired an annual 

 recurring impulse to travel, extremely like, if not identical 

 with, a true migratory instinct, and which can hardly be due 

 to mere memory. 



It is a true instinct which leads the Brent Goose to try to 

 escape northwards; but how the bird distinguishes north and 

 south we know not. Nor do we know how a bird which 

 starts in the night, as many do, to traverse the ocean, keeps 

 its course as if provided with a compass. But we should be 

 very cautious in attributing to migratory animals any 

 capacity in this respect which we do not ourselves possess;! 

 though certainly in them carried to a wonderful perfection. 

 To give one instance, the experienced navigator WrangelJ 

 expatiates with astonishment on the " unerring instinct " of 

 the natives of X. Siberia, by which they guided him through 

 an intricate labyrinth of hummocks of ice with incessant 

 changes of direction ; while Wrangel " was watching the 

 different turns compass in hand and trying to reason the 

 true route, the native had always a perfect knowledge of it 

 instinctively.' 1 Moreover, the power in migratory animals of 

 keeping their course is uot unerring, as may be inferred from 



• Bee. K. P. Thompson on the "Pastiont of .i»<m<i!*, 1851, p. 0; find 



AlUon'l remarks nil thil head in the Cj/elop«tdia of Anatomy and I'/it/Mivlai/i/ 



article " Instinct," p. 88, 



t [I cannot refrain from drawing attention to tin- •trperioritj of scientific 

 met I mii I ami philosophical caution here displayed bj contrasted « it li Prof) 

 ! I i • kel's riews on the same subject, which in presence of Ihis difficult} ut once 

 lude in favour of some mysterious additional sense ( p 85) — Q J. U.J 



X Wrauffeti Tmvtlg, Eng, trans., p. lk>. >'<•'• uU<> Sir <1 dn-y's Expe- 

 dition 1 1 Amtralia, rol. u, |> 11, for interesting socounl of 1 1 » « - powers of 

 tin* Australians in this same respect The nl<l French missionaries used to 

 re that the N. Amerioan Indians were actually guided kj inst.inrt in 

 finding thftti way, 



