288 INSTINCTS OF BIRDS. 



variance with well established facts. Indeed, 

 how very defective and unsatisfactory the argu- 

 ments advanced in support of the hybernating 

 system are, does not require insisting upon, as 

 those who have considered the subject impartially 

 must be well aware, that they are almost wholly 

 founded on the hearsay reports of ignorant and 

 credulous persons. 



The history of the cuckoo proves, most incon- 

 trovertibly, that the propensity to migrate in this 

 species is instinctive, since nearly all the young 

 ones brought up annually in the north of Europe, 

 quit it without receiving the least instruction that 

 such a proceeding is requisite, and without any 

 guide to direct them in their novel undertaking. 

 But I forbear to dwell on the instincts of this 

 extraordinary bird, partly on account of their 

 being so very anomalous, but chiefly because I 

 have considered them at length on a former 

 occasion.* The highly curious fact, that the 

 swallow, house-martin, sand-martin, and puffin 

 sometimes leave their last hatched broods to die 

 of hunger in the nest, in order to accompany 

 their species in their autumnal migration, is alone 

 sufficient to establish the instinctiveness of that 



* See observations conducive towards a more complete 

 History of the Cuckoo, printed in the fourth volume of the 

 new series of the Society's Memoirs. 



