202 THE BIRDS OF HELIGOLAND 



autumn months passes by and across the island in truly astonish- 

 ing quantities. In the autumn, and with favourable weather, the 

 migration commences at about eight o'clock in the morning, with 

 flocks of from fifty to one hundred individuals ; the movement soon 

 passes into a stream of flocks, consisting of from a hundred to at least 

 five hundred examples, and continues in this manner, without gaps 

 of any kind, until two o'clock in the afternoon. We can scarcely, 

 in a case of this kind, assume that we are dealing with a stream or 

 route of migration which just chances to cross Heligoland, for the 

 movement proceeds in equal magnitude from east to west as far as 

 the eye can reach. More than this, on days when powerful migra- 

 tions of this kind take place, the migration-front or column has 

 been seen from boats eight miles north of the island to stretch 

 farther to the north, as far as the limits of vision extend ; while on 

 the south it reached, simultaneously and in equal magnitude, up 

 the Weser, at least as far as Bremerhaven, as was determined from 

 the steamer which regularly plies between this island and the latter 

 place. We thus get a migration-column of at least thirty-six 

 geographical miles in breadth. 



What has just been stated is not only of the highest interest on 

 its own account, but exposes in a very clear light the theory of 

 migration by coast-routes, which has obtained so much favour 

 among ornithologists. Any supporter of this theory, if stationed 

 on any one of the East Frisian Islands from Wangeroog to Borkum, 

 on a day like that described above, would regard and report all 

 he was able to see from the shores of these islands as a most strik- 

 ing proof of his hypothesis, not suspecting in the least that the 

 migration-column extended really from thirty-two to forty miles 

 from the shore farther towards the north. 



The autumn migration of this Crow commences at the end of 

 September, and lasts until the close of November; but scattered 

 flocks are by no means rare, even in the middle of December. 

 This bird is not so fastidious in the choice of weather for its 

 journey as are many other species, which, during some migration 

 periods, are hardly ever seen but is invariably present in large 

 numbers, often in astonishing quantities; such, for instance, accord- 

 ing to my diary, was the case in 1884. The first flocks were 

 seen on the 2nd of October ; from that date very large numbers 

 passed almost daily ; ' thousands ' on the 14th ; ' enormously large 

 numbers ' on the 21st ; on the 24th, ' enormously large numbers of 

 C. comix, monedula, frugilegus, during a light south-east wind, 

 and clear, beautiful weather, comix and monedula travelling in 

 mixed uninterrupted flights, lasting from ten to twelve minutes, 

 and again in similar flights after a short interval the speed of their 



