THE BIRDS OF HELIGOLAND 203 



flight being one hundred and eight geographical miles per hour — 

 the flights being thus from sixteen to twenty geographical miles 

 in length, and their breadth equal the distance from north and 

 south to which either the naked ej'e or the telescope was able to 

 reach.' It is impossible to make even an approximate estimate 

 of the numbers of individuals making up a migration of this kind, 

 even if one assumed that the migration-column, like that observed 

 above, did not exceed thirty-six or forty miles. At the same time 

 an extraordinary strong migration was observed taking place over 

 the North Sea, on the eastern coast of England and Scotland up 

 to the Orkney and Shetland Islands : how far this migration may 

 have extended to the south I have been unable to ascertain. 



An exceptional circumstance, moreover, connected with the 

 above-named autumn mio-ration, was that the hosts of migrants 

 continued to pass the island even late into the afternoon, and a 

 similar phenomenon was observed on the British coast; the 

 'Report on the Migration of Birds for 1S84,' says: 'the rush- 

 appears to have been continuous night and day.' 



The same observation was made here and on the estuary of the 

 Humber, exactly opposite this island, on the 1st, 2nd, and 3rd of 

 jS'ovember of the same year. In other instances, as already stated, 

 the autumn migration always comes to an end at two o'clock in 

 the afternoon, and flocks of hundreds or more arriving after this 

 hour are a rare occurrence. Such late passengers usually fly round 

 the island until evening, when they land and pass the night on any 

 suitable spots. A flock of such birds was once met with by a 

 resident on the plam of the upper plateau during the night. He 

 killed one hundred and eighty-four of them — a welcome windfall 

 for his larder, for the bird forms a favourite dish here. 



In contrast with the autumn migration, the spring passage of the 

 Hooded Crow presents us with one of those wonderful phenomena 

 in which the migration of birds so richly abounds. We have just 

 cited an instance in which these birds evidently passed across the 

 North Sea in the dark ; such occurrences are, however, — in my 

 experience at least — decidedly rare. In the darkness of night the 

 Hooded Crow is a completely helpless creature ; and, accordingly, 

 on the short days of autumn it departs here in the afternoon, and 

 continues its journey as long as there is enough daylight for it to 

 reach the coast of England. For this passage it requires about 

 three hours. In the spring, on the other hand, on their return 

 from England, the flocks not only continue to arrive after sunset, 

 but pursue their journey without stopping, as though aU knew 

 exactly that a flight of another quarter or half-hour would convey 

 them to a safe resting-place close by in Schleswig-Holstein ; never- 



