102 THE BIRDS OF HELIGOLAND 



But this representation of the proceeding, raised though it has 

 been to the dignity of a scientific doctrine, is really nothing more 

 than a plausiblj' sounding fable, in which — quite after the manner 

 of a fable — the old and wise individuals represent the teachers and 

 guides of simple youth. 



In reality, however, this explanation of the question not only 

 lacks all support of actual facts, but is entirely at variance with 

 every observation hitherto made in Nature. 



So far as migratory phenomena are concerned, Heligoland may 

 with truth be called the ornithological observatory of northern 

 Europe, for there is probably no place in the world where this great 

 movement is displayed so markedly, in its original form and com- 

 pleteness, as upon this little island-rock. This speciallj' applies to 

 the autumn migration ; only very few species at this season approach 

 the end of their journey on or near this island, and nearly all the 

 birds which come under observation are seen hastening to their 

 winter quarters in undnuinished numbers and with unabated speed. 



Expressed in the simplest language, the incontestable result of 

 all the numerous phenomena as they come under notice here is as 

 follows : — 



1. That under normal conditions in the case of the three 

 hundred and ninety-six species occurring here, with the exception 

 of a single one, the autumn migration is initiated by the young 

 birds, fi'om about six to eight weeks after leaving their nests. 



2. That the parents of those young individuals do not follow 

 till one or two months later ; and 



3. That of these old birds again, the most handsome old males 

 are the last to set out on the migratory journey. In spring this 

 order of succession is inverted. This will be treated of more fully 

 afterwards. The only exception to the rule to which reference has 

 been made above, is found in the case of the Cuckoo, and this for 

 reasons easy to divine : for having once foisted her egg on another 

 bird's nest, the business of propagation is ended, and having no other 

 object for staying in the north, she forthwith takes her departure. 



Numberless and decisive proofs for the above statements are 

 furnished by those species whose adult plumage differs so markedly 

 from that of the young birds, that one is able to distinguish easily, 

 even at some distance, what stage of age one is dealing with. But 

 even those species whose adult plumage is less striking, can be pro- 

 cured here during the Avhole period of migration in almost any 

 desirable number, so that in all directions there is at one's disposal 

 most ample material for determining each fact with absolute cor- 

 rectness. In support of what has been said above, I will now give a 

 few extracts from my ornithological journal, which I hop)e will 



