HISTORICAL AND EXPERIMENTAL STUDY OF HOMING. 19 



EVIDENCE AGAINST CYON'S "SPURSINN THEORIE." 



On June 16, 1910, a test was made at Tortugas of Cyon's hypothesis which 

 has just been considered. Three noddy terns were captured on the night of 

 June 15. On the morning of June 16 the anterior nares were first sponged out 

 with alcohol to remove all secretion, and then filled with warm wax, packed in. 

 The whole was then coated with asphaltum. The feet of the birds were tied 

 and they were put back in the cages until the asphaltum had had a chance to 

 dry. The feet were left tied also during the transit of the birds, since this 

 prevented them from scratching at the wax and gave them a chance to become 

 habituated to it. Two of the birds, in charge of Mr. Rufus Mills, were sent 

 to Key West and the third (the control) was sent to Loggerhead, 3 miles 

 away. The Key West birds were released at 2 p. m. The nests were observed 

 that night, but apparently they did not return. At daybreak the next day 

 the two birds were both found upon their nests. Since the nest mate was just 

 leaving one of these birds, I am inclined to think that at least one got back on 

 the same afternoon in which it was liberated. The control bird was released 

 at Loggerhead at 7 p. m., in plain sight of Bird Key, with head directed 

 towards Bird Key. Drs. Mayer and Treadwell were both present. This bird 

 flew to the water and bathed, then flew slightly eastward in a straight line to 

 Bird Key; it was on the nest when the experimenter reached there, 30 minutes 

 later. It was found that the plugs in the anterior nares were present in all 

 three birds. The asphaltum was not even scratched and had hardened com- 

 pletely. The birds had resumed their nesting activities. This test (so far as 

 the terns are concerned) seems to be absolutely conclusive against Cyon's 

 hypothesis. 



