ORIENTATION AND ROUTE FINDING 59 



Knock Lightship, Mr Eagle Clarke noticed that 

 birds flew so low along the water that they could 

 not possibly have seen their way. 



It is purely speculative to say that the young 

 bird which travels alone, for it seems certain that 

 many young do travel unguided on their first journey, 

 has an inherited memory of the actual route to be 

 followed, but that it has an hereditary sense of 

 direction, or an hereditary impulse to travel in 

 a certain direction, is quite another matter. The 

 sea, to the young bird, may be a barrier ; it may 

 wander coastwise and be lost, or, if this is the best 

 way, find itself at the desired haven. If the shortest 

 and quickest way is across the ocean, the young bird 

 may brave the perils and succeed, or on this track- 

 less waste it may wander till it sinks to the waves 

 and be added to the long list of failures. 



Certain species summer in Greenland either in 

 the same areas or in areas comparatively near to 

 one another ; some of these travel in autumn south- 

 east, and winter in Europe or Africa, and others go 

 south-west into the States or South America. Most 

 of these are distinctly eastern or western forms, 

 but occasionally American birds are met with in 

 Europe, and European in America. Probably at 

 the start these stragglers joined the wrong band, 

 and travelled for company and unconsciously by 

 the wrong route. Birds drifted to leeward may 



