3 28 Papers from the Marine Biological Laboratory at Tortugas. 



from 0.5 mile and so on. In a short time the bird, on account of the in- 

 creasing distances to which it is carried, combined with its keenness of vision, 

 establishes visual landmarks throughout an enormous territory. A well- 

 trained carrier pigeon could thus hardly be taken into a neighborhood which 

 would be entirely new to it. This presupposes on the part of the bird the 

 ability to establish visual associations at an enormous rate. All the labor- 

 atory tests which animal psychologists have made upon pigeons so far seem 

 to show that the pigeon has no extraordinary ability to establish such asso- 

 ciations.^ 



It occurred to me that any migrating bird ought to possess the func- 

 tion of distant orientation. As a test I made the following experiments: 



Experiment I. 



Six noddies were captured one evening and marked characteristically 

 and individually with oil paints. These birds were put on board the labor- 

 atory launch, which happened to be making a trip to Key West on the 

 following morning. The nests of these birds were all close together and 

 were tagged with a large card in order to facilitate observation. Two of 

 the birds were released at Rebecca Shoal Light, 31.38 km. (19.5 statute 

 miles) from Bird Key; two at Marquesas, 72.75 km. (44.75 statute miles) ; 

 and two at Key West, 106.02 km. (65.8 statute miles). 



I kept their nests under constant observation the whole day long. Natur- 

 ally, since the birds had been without food for some time, and since I had no 

 guarantee that they would immediately seek the nest after reaching the 

 island, I expected the return to the nest to be irregular. The results were 

 as follows : 



The two Rebecca birds, released at 9'' 30" a. m., returned about 12 m. 



The two Marquesas birds, released at 2*" 15"' p. m., returned together 

 at 4 p. m. 



The two Key West birds were released at 6" 30™ p. m. One returned 

 at 7" 30" a. m. the next day, the other at 5" 05"" p. m. These two birds, 

 bearing out my statement that these terns do not fly at night, probably slept 

 in the neighborhood of Key West and left early the next morning. A heavy 

 gale and rainstorm set in very shortly after these birds were released and I 

 doubted very seriously whether they would ever return. Apparently one of 

 the birds was not affected by the storm, while the other was probably blown 

 from its course. 



The respective mates of these birds remained on the eggs the entire 

 time, going neither for food nor water (?). 



Experiment II. 



Three noddies and two sooties (one of the sooties was known to be a 

 male) were captured and marked as above. Their nests were likew-ise 

 prominently marked. On the early morning of Thursday, June 13, these 

 birds were put into a large insect cage and given in charge of Dr. H. E. 

 Jordan, who was returning to New York. He carried these birds via the 



'See Rouse: The Mental Life of the Domestic Pigeon, Harvard Psychological 

 Studies, II, pp. 581-613, and Porter : Further Study of the English Sparrow and Other 

 Birds, Amer. Jour, of Psy., vol. xvii, pp. 248-271. 



