28 The Changeful Skies 



low these birds in fancy, but the fancy will 

 not lead us astray. The direction in which 

 they are going can be determined, the prob- 

 able elevation of their flight-path estimated, 

 the guiding features of their course made 

 probable. -Their purpose can, of course, 

 only be conjeftured. It is not strange that 

 birds of many if not all kinds travel in the 

 dark, for this absence of light is but relative. 

 The stars of themselves are nothing to the 

 birds but as they are reflected in the water. 

 When visible in this way, they aft as finger- 

 posts along a river valley. Such doubtless 

 is the guide to much of the annual migrato- 

 rial flight ; and the black lines of mountains 

 would be readily recognized as such, while 

 the lights beyond would indicate those of 

 another valley, with its star-refleling river. 

 So comprehensive is a bird's-eye view that 

 migration has nothing marvellous about it. 

 May it not be, too, that these long journeys 

 are commenced in daylight, and that when 

 great elevation is reached the direction at the 

 outset can be readily maintained ? A bird 

 does not fly in a circle, as a man walks when 

 lost in the woods. When fog or excessive 

 cloudiness is encountered, wandering birds 



