358 !^[p:yTAL EVOLUTION IX ANIMALS. 



the nmnbers of lost swallows often met with by ships in tlie 

 Atlantic : the migratory salmon, also, often fails in returning 

 to its own river, " many Tw^eed salmon being found in the 

 Forth." But how a small and tender bird coming froin 

 Africa or Si:iain, after traversing the sea, finds the very same 

 hedge-row in the middle of England, where it made its 

 nest last season, is truly marvellous.* 



Let us now turn to our domesticated animals. Many 

 cases are on record of animals finding their way home in a 

 mysterious manner, and it is asserted that Highland sheep 

 have actually swum over the Frith of Forth to their home a 

 hundred miles distant ;t when bred for three or four genera- 

 tions in the lowlands, they retain their restless disposition. I 

 know of no reason to doubt the minute account given by 

 Hogg of a family of sheep which had a hereditary ijropensity 

 to return at the breeding season to a place ten miles off, 

 whence the first of the lot had been brought ; and, after their 

 lambs were old enough, they returned by themselves to the 

 place wdiere they usually lived ; so troublesome was this in- 

 herited propensity, associated with the period of parturition, 

 that the owner was compelled to sell the lotj Still more 

 interesting is the account given by several authors of certain 

 sheep in Spain, which from ancient times have annually 

 migrated during May from one part of the country to another 

 distant four hundred miles : all the authors§ agree that " as 

 soon as April comes the sheep express, by curious uneasy 

 motions, a strong desire to return to their summer habita- 



* The number of birds wliieli by chance visit the Azores (Consul C. Hunt, 

 ill Journ. Geograph. Soc, toL xv, Pt. 2, p. 282), so distant from Evirope, is 

 probably in part due to lost directions during migration : W. Thompson 

 {Nat. Hist, of Ireland, " Birds," vol. ii, p. 172) shows that N. American birds, 

 which occasionally wander to Ireland, generally arrive at the period when 

 they are migrating in N. America. In regard to Salmon, see Scope's Days 

 of Salmon Fishing, p. 47. 



f Gardener'' s Chronicle, 1852, p. 798 : other cases are given by Youatt on 

 Sheep, p. 377. 



X Quoted by Youatt in Veterinary Journal, vol. v, p. 282. 



§ Bourgoanne's Travels in Spain (Eng. trans.), 1789, vol. i, pp. 38-54. 

 In Mills' Treatise on Cattle, 1776, p. 342, there is an extract of a letter from 

 a gentleman in Spain from which I have made extract. Youatt on the Sheep, 

 p. 153, gives references to tln'ee other publications with similar accounts. I 

 may add that von Tschudi {Sketches of Nature in the Alps, Eng. trans., 

 1856, p. 160) states that annually in the spring the cattle are greatly excited, 

 when they hear the great bell which is carried ^vith them ; well knowing that 

 this is the signal for their " approaching migration " to the higher Alps. 



