3 2S Papers from the Marine Biological Laboratory at Tortngas. 



from 0.5 mile aiul 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, 

 estabHshes 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 c;'' 30"' a. m., returned about 12 m. 



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

 ai 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 S*" 05 p. m. These two birds, 

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

 m the neighborhood of Key West and left early the ne.xt 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 probabl}- 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) vi^ere captured and marked as above. Their nests were likewise 

 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 Otiier 

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



