VIII. WHAT GUIDES BIRDS DURING 

 THEIR MIGRATIONS? 



This question involuntarily suggests itself after we have followed 

 the flights of the feathered wanderers, hastening onwards with 

 storm-like rapidity, at elevations level with the clouds : — B}^ the 

 aid of what capacity are they enabled, on pitch-dark nights in 

 October and November, to take up the right path and to pursue it 

 unerringly to the end, over, say, a sea of more than four hundred 

 miles in breadth, like the German Ocean between the west coast of 

 Slesvick-Holstein and the east coast of England ? Man, in spite of 

 his senses and intellectual faculties, is not able to continue moving 

 in a straight line for even as much as a mile in complete darkness 

 or dense fog; whereas birds fly every autumn, without signs or 

 landmarks, from the far east of Asia to the west of Europe, and 

 from the North Cape of Scandinavia to the south of Africa, tra- 

 versing in each case a distance of considerably more than four 

 thousand miles. 



What, however, adds considerably to the truly wonderful 

 nature of this phenomenon, is the fact that the young birds of the 

 year, their age not exceeding six or eight weeks, perform this first 

 journey of their hfe with the same unerring certainty as the old 

 individuals which follow them a month or two later, and which, 

 moreover, have already travelled over the same road on previous 

 occasions. 



Any one who, on dark, starless autumn nights, has heard the 

 babel of voices of these hundreds of thousands and even millions 

 of birds travelling past him overhead, in one fixed direction 

 and in undiminishing numbers for the length of whole months, 

 without the help of any guiding mark discernible by human eye, 

 cannot fail to be led, by the supreme grandeur of this phenomenon, 

 to speculate as to what kind of capacities the unfailing perform- 

 ance of such an act is due ; more especially if, like myself, he has 

 for more than half a century watched the phenomenon recurring 

 regularly at each solstice with the same unerring precision as the 



