140 Cole, The Tagging of Wild Birds. [^k 



of returns may be expected from this sort of work. The use of 

 tags by Dr. Watson * to study the homing instinct of Noddy and 

 Sooty Terns at the Tortugas, illustrates the way in which the 

 method may be applied experimentally. 



Now as to the sort of results that may be expected from this 

 method of investigation: Not only will it aid in the study of the 

 general migration of a species, but by giving us records of the 

 movements of individual birds, will assist us in analyzing the 

 factors connected with migration in detail. A moderate number 

 of successful "returns" should help in settling such questions as: 

 Are the residents of a locality, or the migrants going further on, 

 the first to arrive in the spring ? Do the residents leave before the 

 northern contingent arrives in the fall, or are they the last to go? 

 Do males, females and young travel together, or do one or another 

 go ahead ? What is the exact route taken from any locality, and is 

 the same route travelled each year? Furthermore it must be 

 borne in mind that the migration problem is probably but a special 

 phase of the homing problem, and that such questions as whether 

 birds commonly return to the same locality to breed, and whether 

 the young return to the locality in which they were reared, are very 

 pertinent to its solution. I should like to emphasize further the 

 importance of the bearing of the homing instinct, both in birds and 

 in other animals, were there time. I can only express it, however, 

 as my firm belief that a comparative study (observational com- 

 bined with experimental when possible) of such phenomena as the 

 annual migrations of the fur seals, and of bats, and of many fishes, 

 as well as of the homing of animals in general (toads, ants, bees, 

 and in fact all animals which return to a definite place) is going 

 to be of the greatest value in understanding the "mysteries" of the 

 migration of birds, where the instinct appears to be developed in its 

 highest form. 



Answers to certain of the questions stated above have already 

 been found, but most of them depend upon a knowledge of the 

 movements of individual birds, and to ascertain these we must have 

 some means of identifying the individual. This is the purpose 

 served by the numbered bands. 



1 Watson, John B. 'The Behavior of Noddy and Sooty Terns.' Publication 

 103, Carnegie Inst. Wash., Paper VII, pp. 187-225, pll. i-xi, March, 1909. 



