SOME MODERN VIEWS 25 



Merlin) have been detected snatching the weary voyagers 

 as they i\y distracted round the lanterns at night. 



Speed of Migrants. — The speed at which birds 

 travel when on their migratory journeys has been much 

 discussed. I shall give my own experiences and 

 estimates when relating what I witnessed when in the 

 Kentish Knock lightship, where I had many oppor- 

 tunities of observing birds crossing the North Sea. I 

 do not believe that any species exceeds loo miles per 

 hour, and I doubt if such a speed is maintained by birds 

 on their migrations. Gatke,^ however, would endow 

 them with amazing powers in this respect (as much as 

 207 miles — " 180 geographical miles " — per hour). The 

 data, however, upon which his estimates are based are 

 of the very flimsiest nature, and will not stand the tests 

 very properly imposed by modern scientific investigators. 



How ARE THE MIGRANTS GuiDED? — There still remains 

 for consideration another question, perhaps the most 

 interesting, certainly the most puzzling, of all. We have 

 seen that when on their journeys, the migrants not only 

 travel vast distances overland, but also cross pathless 

 seas and oceans. The question is — How do they find 

 their way? How are they guided .-^ Here we are face 

 to face with what is rightly regarded as one of the 

 greatest mysteries to be found in the animal kingdom. 



Many explanations have been offered. Among others 

 it has been suggested that birds are endowed with some 

 organ which makes them sensitive to the magnetism of 

 the earth, and thus enables them to steer their course as 

 a sailor steers his ship. Others look to sight and 

 memory, both of which birds possess to a remarkable 

 degree. It is possible that these faculties would suffice 



1 Die Vogchvarte Helgoland, 190I5 P- 68. 



