The Behavior of Noddy and Sooty Terns. 195 



island for distances greater than 15 knots. Further observations are sadly 

 needed at this point, specially with reference as to whether the birds may not 

 possibly journey further in other directions than in the easterly one. Also 

 as to whether the birds have to go further during stormy weather in order 

 to obtain their food. At all of the above distances, the lighthouse on Logger- 

 head Key, 160 feet in height, could be " sighted " by the birds at the 

 elevation at which they fly. 



From other observations, too numerous to mention separately, I con- 

 clude that all birds return to the island at night. Many times just at sun- 

 down I have come from Loggerhead Key to Bird Key. The terns are com- 

 ing in by hundreds and thousands, flying low over the water. By the time 

 twilight has faded the water is entirely deserted. Several trips made to Fort 

 Jefferson late at night showed that these birds do not leave the island at night. 

 The moment the island is reached, however, no matter at what hour of the 

 night, one finds the sooties busily flying from one place to another on it. 



While I made these observations as carefully as I could, I realize that 

 conclusive deductions can not be made until a more extended study has been 

 undertaken. 



THE MATING OF THE NODDIES AND OF THE SOOTIES. 



According to Thompson,^ both species mate before reaching the island. 

 Whether or not this statement is true can not be answered from my own 

 observation. I did not begin my work upon the birds until May 4. Since 

 they reached the island upon April 29, I could not observe their early be- 

 havior. But as I arrived only 5 days later than the birds= and found both 

 species actively engaged in nest-building and some beginning to lay,'' it 

 seems quite clear that mating is either a very simple process, requiring little 

 time, or else it had been accomplished before or during migration. A com- 

 plete account of mating can scarcely be given until we know more of the 

 life of these birds before their northern migration begins: Are they gregari- 

 ous previous to it; if so, to what extent? Are the partnerships formed dur- 

 ing the mating season kept after the young are reared? What are their 

 habits in feeding and in roosting, etc.? Do their habits change at the ap- 

 proach of the time for migration? What is the length of time for migra- 

 tion? What are their habits during migration (i. e.. do thev stop on land at 

 intermediate points), etc.? 



My notes contain a rather full account of a striking series of reactions 

 between two noddies, which I took to be a case of mating and choice of 



' Op. cit., p. 78. 



^l am quite sure that I reached the island before many of the birds. Apparently 

 the birds, the sooties at least, arrive in groups stretching over a period of about two 

 weeks. 



^Two noddy eggs were found May 4. while the soolv eggs were first found on 

 May 7. 



