254 THE BIEDS OF HELIGOLAND 



arrives during the course of March, the last stragglers bringing the 

 spring migration to a close in the middle of April. The birds 

 return from their breeding quarters from the middle of October to 

 the middle of November; after the latter month, however, one 

 may expect to come across solitary examples, or even groups of 

 from twenty to thirty individuals, at all times of the winter. Thus, 

 at the end of December 1876, some twenty birds visited my garden 

 almost daily, where they greedily devoured the berries on the 

 thorn-bushes. Despite the sharp winter weather, these birds were 

 very plump, as was also the case with the numerous Fieldfares 

 which accompanied them. 



Winter visitants like these are invariably old birds, the large 

 majority males, with orange-yellow bills ; these, doubtless, had 

 purposed wintering in their breeding quarters, but were driven out 

 by the advent of severe cold and snow ; indeed, as soon as the 

 weather becomes milder, they at once disappear again. 



Unlike all its other generic relatives, this Thrush by preference 

 frequents the grottos and clefts at the base of the rock. But birds 

 which have chosen such spots for their place of residence during the 

 winter months, have fed largely on the larvae of marine insects, which 

 occur there in great abundance, and have thereby acquired so un- 

 pleasant a srnell and taste that they are literally unfit for food. 



The Blackbird furnishes excellent proof of the difference in the 

 time of the migratory flight of different ages and sexes ; for the 

 glossy black colour of the earliest spring arrivals leaves no doubt 

 as to their being old males. In the course of a week or two they 

 are joined by the greyish-brown females ; with the gradually 

 increasing numbers of the latter are associated young birds, in whose 

 plumage the reddish-brown colour is more pronounced. Now 

 and again a solitary black individual with orange bill may be found 

 among these last stragglers; these invariably, as is proved on 

 examination after capture, have suffered some injury or other. 

 Some of the toes, or a foot, have been lost ; or the tail or one of the 

 wings has suffered a great loss of feathers ; or some other injury 

 sufficient to delay their passage has been sustained. The autumn 

 migration proceeds in similar unchanging sequence ; only, in this 

 case, the migration begins with the arrival of the young birds, and 

 terminates with that of the old ones. Hence it has become pro- 

 verbial among the fowlers of Heligoland that when the Ouhl- 

 nabbeten i.e. ' the yellow-billed birds ' begin to arrive, the Thrush 

 season is on the wane. t 



The spring and autumn migration of all other species proceeds 

 in the same sequence as regards age, with the sole exception of 

 the Cuckoo. 



