THE SENSE OF DIRECTION 115 



the whole of the distance they are to fly, draws a 

 broad distinction between the homing of individual 

 birds and the instinct which directs migration, 

 common to every individual of a species. It is doubt- 

 ful if this distinction can be maintained, for not 

 only are there well-authenticated cases in which un- 

 trained pigeons have "homed" long distances, but 

 the very methods of pigeon-training go far to show 

 that the birds possess a sense of direction. 



If homers were only trained over short stages, say, 

 eight to ten miles at a time, they might actually 

 learn the whole of their route by sight ; but they 

 are occasionally flown from Brighton to London at 

 the first toss without any intermediate stages, so that 

 if they are not guided by any sense of direction, they 

 must be conceded powers of sight which would be at 

 least as wonderful. Under perfect atmospheric con- 

 ditions it would, no doubt, be possible from a height 

 of only a few hundred feet above Brighton to see 

 on the horizon a dark mass which would represent 

 London ; but how, failing a sense of direction, could 

 a bird which had never seen the great city from 

 such an aspect before possibly know what that mass 

 represented, much less recognise in it any particular 

 London landmarks ? Moreover, if the best authenti- 

 cated examples of the homing instinct in various birds 

 and animals are graded and classified, we believe that 

 the results will show, on a graduated scale, the con- 

 nection between the least remarkable instances which 

 can be explained by reference to experience or reasoning 

 power, and the most remarkable, such as the migration 

 of birds by night across wide intervals of sea, in 



