ORIENTATION AND SENSE OF DIRECTION 227 



alone was involved. A comparison of the ganglion brain of the wasp 

 with that of the bird can leave little doubt that the latter is capable 

 of far greater powers of perception and memory, as it is of vision and 

 flight (cf. Grinnell, loc. cit., page 24). As to the homing of the 

 noddies and sooties tested at the Tortugas, the results were regarded 

 by the authors as being negative in character (Watson and Lashley, 

 1915), though they opposed the assumption of some new mysterious 

 sense. However, an examination of their tables shows that there were 

 40 returns and 7 failures when the point of release ranged from 19 

 to 66 statute miles, and 17 returns to 59 failures when it was from 

 418 to 855 miles. This accords with the expectation on the basis of 

 memory for location, while a special "sense of direction" should have 

 permitted all the birds to return at all distances, barring accident. 



The existence of a special sense or an automatic instinct is rendered 

 still more improbable by the behavior of homing pigeons, in connec- 

 tion with which Thomson (1926:313) states that "the remarkable per- 

 formances recorded are not explicable by assuming a hereditary fac- 

 tor." In their training, not only do few manage to achieve the longer 

 returns, but it is also known that the birds make definite observations 

 to ascertain the direction of flight, much after the manner of wasps. 

 Moreover, they are unable to find their way from distances of a few 

 miles in fog and they are confused by thunderstorms. According to 

 Rodenbach (1895; cf. Watson and Lashley, loc. cit.), they experience 

 difficulty in returning home at night or in cloudy weather if the sun 

 is obscured, while Hachet-Souplet (1903) states that blind birds are 

 C}uite incapable of finding their way home, even when released but a 

 few miles away. 



In his valuable summary of recent progress (1936: 515), Thomson 

 cites the work of Riviere (1929) with untrained birds and those of 

 Casamajor (1927) with birds partially handicapped, neither of which 

 supports the assumption of a homing instinct or a special sense of di- 

 rection, apart from observation or tropistic response. 



Results of the same general tenor have been secured by Riippell 

 (1934, 1935) with the starling {Sturnus vulgaris L.). Seven out of 11 

 birds returned to the breeding place from a distance of 71 miles, the 

 shortest time being 281/2 hours, while but 2 out of 6 came back from 

 a distance of 127 miles, requiring 4 and 9 days, respectively. In other 

 tests, nearly two-thirds of the birds failed to return, namely, 233 out 

 of 353. Hilprecht (1935) released a thousand birds at distances of 

 130 to 290 miles, but obtained only 33 returns and at intervals of a 

 month or more (cf. Thomson, 1936:516-7). 



The question of the guidance of young storks has recently been 



