SOME MODERN VIEWS 29 



these it appears that fifteen marked Noddy and Sooty 

 Terns were taken from their nesting haunts at Bird 

 Key, Tortugas, and released at distances varying from 

 20 to 850 statute miles, and that thirteen of them 

 returned to the Key. Among the thirteen were several 

 birds which had been taken by steamer as far north as 

 Cape Hatteras, before being freed. "This experiment," 

 Mr Chapman proceeds to say, "is by far the most 

 important in its bearing on bird-migration of any with 

 which we are familiar. It was made under ideal con- 

 ditions ; neither the Noddy nor the Sooty Tern range, 

 as a rule, north of the Florida Keys. There is no 

 probability, therefore, that the individuals released had 

 ever been over the route before, and, for the same reason, 

 they could not have availed themselves of the experience 

 or example of migratory individuals of their own species ; 

 nor, since the birds were doubtless released in June or 

 July, was there any marked southward movement in the 

 line of which they might follow. Even had there been such 

 a movement, it is not probable that it would have taken 

 the birds south-west to the Florida Keys, and thence 

 west to the Tortugas. This marked change of direction, 

 occasioned by the water course, which the birds' feeding 

 habits forced them to take, removes the direction of the 

 wind as a guiding agency, while the absence of landmarks 

 over the greater portion of the journey makes it impro- 

 bable that sight was of service in finding the way. . . . 

 We cannot but feel that the experiments with these birds 

 constitute the strong^est aro-ument for the existence of a 

 sense of direction as yet derived from the study of birds. 

 With this established, the so-called mystery becomes no 

 more a mystery than any other instinctive functional 

 activity." 



