APPENDIX. 



[The full text of a part of Mr. Darwin's cliapter on 

 Instinct wiitten for the " Origin of Species," but afterwards 

 suppressed for the sake of condensation.] 



Migration. — The migration of young birds across broad 

 tracts of the sea, and the migration of young salmon from 

 fresh into salt water, and the return of both to their birth- 

 places, have often been justly advanced as surprising in- 

 stincts. With respect to the two main points which concern 

 us, we have, firstly, in different breeds of birds a perfect 

 series from those which occasionally or regularly shift their 

 quarters within the same country to those which periodically 

 pass to far distant countries, traversing, often by night, the 

 open sea over spaces of from 240 to 300 miles, as from the 

 north-eastern shores of Britain to Southern Scandinavia. 

 Secondly, in regard to the variability of the migratoi'v 

 instinct, the very same species often migrates in one country 

 and is stationary in another ; or different individuals of the 

 same species in the same country are migratory or stationary, 

 and these can sometimes be distino-uished from one another 

 by slight differences.* Dr. Andrew Smith has often re- 

 marked to me how inveterate is the instinct of migration in 

 some quadrupeds of S. Africa, notwithstanding the persecu- 

 tion to which they are in consequence subjected : in K. 

 America, however, persecution has driven the Buffalo within 



* Mr. G-ould lias observed tliis fact in Malta, and in Tasmania in Ihe 

 soutliern liemisphere. Eeclistein {Stuhenvogel, 18-40, s. 293) says that in 

 Grermany the migratory and non-migratory Thrushes can be distinguished by 

 the yellow tinge of the soles of their feet. The Quail is migratory in 

 S. Africa, but stationary in Kobin Island, only two leagues from the con- 

 tinent {Le Vaillanfs Travels, vol. i, p. 105) : Dr. Andrew Smith confirms 

 this. In Ireland the Quail has lately taken to remain in numbers to breed 

 there (W. Thompson, Nat. Hist, of Ireland, vide " Birds," vol. ii, p. 70). 



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