162 



THE WORLD OF LIFE 



They usuallj take place on dark nights, sometimes in mil- 

 lions; at other times, a week will sometimes pass with only 

 a few stragglers. Of one such pitch-dark night Mr. Seebohm 



writes : 



Fig. 22.— The Light- 

 house at Heligoland on a 

 Migration Night. 



" Arrived at the lighthouse, an intensely interesting scene pre- 

 sented itself. The whole of the zone of light within range of the 

 mirrors was alive with the birds coming and going. Nothing else 

 was visible in the darkness of the night, but the lanthorn of the 

 lighthouse vignetted in a drifting sea of birds. From the darkness 

 in the east, clouds of birds were continually emerging in an unin- 

 terrupted stream ; a few swerved from their course, fluttered for a 

 moment as if dazzled by the light, and then gradually vanished 

 with the rest in the western gloom. ... 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 that the lighthouse- 

 man succeeded in capturing amounted to nearly 300." 



He also tells us that 15,000 sky-larks have been caught 

 on Helifi^oland in one nio-ht ; and all aiiTee that the count- 



