294 BRITISH SEA BIRDS. 



houses and light-vessels. Vast numbers of birds 

 kill themselves every spring and autumn by 

 striking against these gleaming beacons of the 

 coast. From this great mortality, however, 

 naturalists have learnt much concerning the annual 

 movements of birds ; for the records kept by 

 our light men, extending, as they do, over a 

 number of years, of these fatalities and periodical 

 visits of migrants, are most instructive and sugges- 

 tive. Some of the scenes witnessed at these light- 

 houses and vessels, during the seasons of migratiou 

 especially in autumn are intensely interesting. 

 These beacons are most fatal during cloudy 

 weather ; few birds strike on clear and cloudless 

 nights. Odd birds are continually striking against 

 the lanterns. Now and then, however, there come 

 nights when birds swarm like bees round the lamps, 

 and kill themselves in thousands by striking against 

 the glass, sometimes with such force as to shatter it 

 to fragments. The illustration at the head of the 

 present chapter also shows another peril of migra- 

 tion. Many nets are placed on the shores of the 

 Wash, and great numbers of birds are, or used to 

 be, caught during the autumn months. Information, 

 however, has recently reached me that the birds 

 are learning, by many years' experience, to avoid 

 these snares, flying over instead of through them, 

 and that nothing like the numbers are caught 

 nowadays. Fifteen years ago thousands of birds 

 must have been taken in these nets. 



