66 THE BIRDS OF HELIGOLAND 



Bluethroat travels during the night, setting out at dusk and end- 

 ing its journey at daybreak, or immediately after sunrise. Hence 

 it accomplishes a flight of more than 1600 geographical miles from 

 Egypt to Heligoland in the course of a spring night of scarcely nine 

 hours, giving the almost miraculous velocity of one hundred and 

 eighty geographical miles per hour. The species does not winter 

 further west than Central Africa, nor do its breeding quarters 

 extend farther to the westward than Norway ; there can therefore 

 be no doubt as to the identity of the examples found in Heligoland 

 with those from Central Africa. 



The fact that this bird is never seen among those Avhich are 

 captured here at night at the lighthouse, but invariably arrives only 

 about dawn, furnishes a further proof that it does not alight for 

 rest during the spring migration, nor reach this island from any 

 stations nearer than its winter quarters in Africa. 



Judging from its general habits, there is no reason for consider- 

 ing this Bluethroat as possessed of more than moderate capacities 

 for flight. Its mode of life throughout the whole year, with the 

 exception of the one particular migration night, is such that, 

 according to the theories of Natural Selection and Heredity, its 

 powers of flight should, through disuse, have long since retrograded 

 to such an extent as to have rendered it quite unequal to perform 

 feats like that mentioned above. Quite on the contrary, however, 

 its powers of flight must have acquired an extraordinary develop- 

 ment for the special purpose of migration; for, under ordinary 

 conditions, the bird lives on the ground, hopping about all day 

 with wide leaps, and only using its organs of flight under stress of 

 necessity. If, therefore, a bird like this, among the varied activities 

 of whose life flying is almost an exception, is nevertheless capable 

 of accomplishing such wondrous feats on one single occasion in the 

 course of a whole year, what extraordinary achievements in this 

 direction may we not expect from such expert and energetic flyers 

 as the Hobby, the Swallow, and the like. Future investigation will, 

 without doubt, bring to light astonishing results in this field of 

 inquiry. 



From the above considerations it appears that birds not only 

 are possessed of an astonishing and probably quite unsuspected 

 power of flight, but, further, that their migration flights are accom- 

 plished at a rate of speed equally astounding and unconjectured. 

 The wide divergency between the results of my observations and 

 those arrived at by Dr. von Middendorff most probably has its 

 explanation in the considerable difference of latitude in Avhich 

 our observations were respectively carried on. In Heligoland the 

 migratory hosts are seen, at both migration-periods of the year alike. 



