HISTORICAL AND EXPERIMENTAL STUDY OF HOMING. 43 



Only birds whose mates did not return are listed in this table. The data in 

 all of these studies on retention of the nest suffer by reason of the fact that 

 sex was not determined. No. 23, deserting at the end of 1 1 days, was undoubt- 

 edly a female. 



RETENTION OF NESTING HABITS AND NEST LOCALITY IN THE BIRD REMOVED 



FROM THE NEST (R). 



In order to test the limits of retention of nest locality, 10 noddies and 10 

 sooties were captured and their nests plainly marked on May 12, 1913. They 

 were individually marked with oil paints, carried to Loggerhead Key, and kept 

 in a large fly-, mosquito-, and ant-proof cage.* We planned to release these 

 birds at varying intervals and to note whether they returned and resumed 

 normal nesting activities with their mates. The experiment was planned to 

 give the limits of time within which complete resumption of nesting activities 

 might take place after forcible detention on Loggerhead. The test was com- 

 pleted as follows : On the day any given bird was to be released on Loggerhead 

 the experimenter stood before the nest while an assistant took the motorboat 

 and went to Loggerhead to release the bird. The watches of the experimenter 

 and the assistant were set together. The following summary is taken from 

 the notes of one of the observers. 



11 days: 



Noddy No. 11 was released at 4 h 24 m p. m. after spending 11 days in captivity. Upon 

 release at Loggerhead the bird flew out to water and thoroughly bathed. There- 

 upon it flew off straight to Bird Key. Bird was fed before leaving. Arrived at 

 rim of nest at 4 h 34 m . Total time 10 minutes. Flew away an instant after 

 alighting. No sign between mates was made. O had been very faithful. Upon 

 R's return did not attack, as it surely would have done had R been a stranger. 

 After 26 minutes R returned to island and flew to house top. Remained there 8 

 minutes, then came down and arriving at nest bowed (plate 3, fig. 1) to mate. 

 Mate bowed in return. R did not sit on egg that day, but brooded it the following 

 day in a normal manner. 



15 days: 



Noddy No. 17 was released at ll h 33 m a. m. after 15 days. Arrived at nest at ll h 57 m . 



Time, 24 minutes. Left nest and did not reappear before observer left at l h 15 m . 



O was not on the egg but on nearby limb. Bird did not appear again that day 



while I was present. On the following morning I saw O repeatedly drive R away. 



Friendly relations were never resumed. 

 Sooty No. 12 was released at the same time. This bird never appeared at its nest. 



16 days: 



Noddy No. 18. Released at 5 p. m. after 16 days. Would not leave Loggerhead. 



Flew to water, thereupon to bow of one of the boats, then underneath dock. 



Finally disappeared from Loggerhead but never appeared at its nest. 

 Sooty No. 5. Released at same time as No. 18. Flew out over gulf to Southwest, then 



turned and started towards Bird Key. Never was observed at nest. 



*Very fine galvanized wire netting inclosed all sides of the cage. The cage was floored and 

 covered with wooden boards. It was mounted upon four legs, 3 feet in height, and the bottoms 

 of the legs were inserted into large pails kept filled with water. Fresh sand was kept on the floor 

 of the cage. The birds were fed with minnows. At first they would not eat and some had to be 

 forced to eat. After 4 or 5 days the majority of them began to eat. For some reason many of 

 the birds lost flesh rapidly and died, even in cases where they apparently ate the normal number 

 of minnows. Of the 20 birds in captivity only 13 lived through the experiment. 



