MIGRATION 97 



Not until the erection of lighthouses along our coasts did 

 we gain an opportunity of realising the magnitude of migratory 

 movements, and of the astounding numbers of the birds which 

 participate therein. But by a strange irony these beacons of 

 safety to the human race have become veritable death-traps to 

 the birds, for the lanterns, when sending forth their beams for 

 the guidance of those who go down to the sea in ships, exert at 

 the same time a fascination for the winged wanderers which 

 seems to be absolutely irresistible. In thousands they dash 

 themselves against the blinding light, and in thousands they fall 

 stunned on to the rocks below, or into the surging sea, so 

 making an annual death-roll which is positively appalling. On 

 clear and moonlit nights such tragedies are largely, if not en- 

 tirely averted, but cloudy skies and a mist-like rain are fatal, 

 for the light reflected on the latter gains a peculiar brilliancy 

 which appears to exert a dazzling effect which these birds can- 

 not escape. Two of many instances given by Gatke show the 

 extent of these visitations. From ten o'clock on the night of 

 the 28th of October, 1882, to the next morning, Goldcrests 

 eddied thick as flakes in a heavy snowfall round the lighthouse 

 on the little island of Heligoland ; on the morrow they literally 

 swarmed over every square foot of the island ; and twelve 

 months later Hawks in myriads thronged to its bright beams 

 for four nights in succession, accompanied by Starlings in hardly 

 fewer numbers. But "these great hosts," remarks Professor 

 Newton, • "consist usually of many kinds of birds congruous 

 only in their congress — Larks and Lapwings, Starlings and 

 Sandpipers, Fieldfares and Curlews, Golden-crested Wrens and 

 Golden Plovers, Oyster-catchers and Owls — while the air is 

 filled with their cries, among which are several that are wholly 

 unrecognisable, for it would seem that some birds have a lan- 

 guage that they use only when migrating. Otherwise is it with 

 the return of the wanderers in spring, when the exciting scenes 

 of autumn are seldom if ever presented, yet under a moonless 

 and clouded sky the wakeful ear may often catch positive evi- 

 dence of what is going on aloft, though owing to the smaller 

 numbers (for at that season it is only the birds which are about 

 to breed that pass) and the shorter nights, the movements at- 

 tract far less attention. Generally troop after troop of the 

 travellers succeeds in orderly, and what has been called 

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