THE SENSE OF DIRECTION. 47 



of flying many times a day from one end of the room to the 

 door of its cage. When the cage was removed a distance of a 

 few feet to one side, I found that the Canary flew to the exact 

 spot where the door had been.* It is thus apparent that the 

 Canary had a knowledge of the position of the cage door in 

 space, and that it did not need to look for the entrance in order 

 to fly accurately towards it from a distant point. Visual per- 

 ception of the objective, as a means of guidance, was therefore 

 not used by the Canary in making habitual flights. 



Topham and others, especially Bethe, arrived at a similar 

 result with Bees, the latter emphasising the idea of a locality in 

 space as the virtual nature of the destination, a remarkable 

 circumstance long since recognised, for Thompson records that 

 Bees " know their hive more from its locality than from its 

 appearance." Watson made analogous experiments on Terns, 

 and with like results.! He was able to show that the environ- 

 ment, the egg, and the nest itself, could be eliminated, or 

 completely altered, without affecting the capacity to return to 

 the immediate locality of the nest, and it is this — the locality 

 of the nest — that Prof. Watson regards as the principal factor in 

 homeward orientation. From the results of his experiments 

 Prof. Watson suggests that " if adjustment (i.e. to the nest) is 

 made in terms of visual data, the visual environment which 

 serves as the stimulus must be complex and have a wide 

 extension." But he is not prepared to admit that adjustment 

 takes place in terms of vision alone. These experiments are 

 particularly valuable in that they were made on birds whose 

 European representatives, according to Slonaker, are capable of 

 binocular vision, J My own observations apply to birds which 

 have only one area for clear vision in each eye, and which 

 apparently do not have binocular vision. Thus, in spite of the 

 capacity to see clearly ahead, the Terns were not aware of any 



- The experiment was repeated almost daily, and often unintentionally 

 for several years on the same bird, and on a second Canary for a shorter 

 period. No material variation in the result was observed. 



f Topham, 'Nature,' April, 1874, p. 464; Bethe, Pfliiger's Archiv. 

 Bd. lxx. s. 72, 1898 ; Thompson, ' Passions of Animals,' p. 53, 1851 ; 

 Watson, 'Carnegie Institution, Washington,' Publ. No. 103, p. 227, 1908. 



| ' Journal of Morphology,' vol. xiii. p. 445, 1897. 



