204 THE MIGRATION OF BIRDS 



occasionally one fluttered against the glass like a moth 

 against a lamp, tried to perch on the wire netting and 

 was caught by the lighthouse man. I should be afraid 

 to hazard a guess as to the hundreds of thousands that 

 must have passed in a couple of hours ; but the stray 

 birds which the lighthouse man succeeded in securing 

 amounted to nearly 300. The scene from the balcony 

 of the lighthouse was equally interesting ; in every direc- 

 tion birds were flying like a swarm of bees, and every 

 few seconds one flew against the glass. All the birds 

 seemed to be flying up wind, and it was only on the lee 

 side of the light that any birds were caught. They were 

 nearly all skylarks. In the heap captured was one red- 

 start and one reed-bunting. The air was filled with the 

 warbling cry of the larks ; now and then a thrush was 

 heard : and once a heron screamed as it passed by. The 

 night was starless and the town was invisible, but the 

 island looked like the outskirts of a gas-lighted city, 

 being sprinkled over with brilliant lanterns. Many of 

 the larks alighted on the ground to rest, and allowed the 

 Heligolanders to pass their nets over them. About 

 three o'clock A.M. a heavy thunderstorm came on, with 

 deluges of rain ; a few breaks in the clouds revealed the 

 stars ; and the migration came to an end or continued 

 above the range of our vision. 



The conclusion I came to after my Heligoland expe- 

 rience was that the desire to migrate was an hereditary 

 impulse, to which the descendants of migratory birds 

 were subject in spring and autumn, which has during the 

 lapse of ages acquired a force almost, if not quite, as 

 irresistible as the instinct to breed in spring. On the 

 other hand, the direction in which to migrate appears to 

 be absolutely unknown to the young birds in their first 

 autumn, and has to be learnt by experience. The idea 



