MIGRATION. 169 



is by no means certain that they do this in a systematic man' 

 ner, or that their leadership is distinctly recognized or realized 

 by the younger birds who accompany or follow them. On the 

 contrary, the latter are probably directed as well as perhaps 

 urged onward, simply by the contagion of general example and 

 a desire to keep within sight or hearing of their companions, 

 both strong influences with birds, especially very young ones 

 which have only lately passed from a state of complete de- 

 pendence and are still not wholly independent. That a very 

 few experienced old birds could thus direct and guide the 

 movements of thousands of inexperienced young is to my mind 

 obvious. . . . 



" It is not necessary to assume, nor in my opinion is it likely, 

 that these flocks keep intact throughout the whole of their long 

 journey. . . . But whether among friends or strangers, the 

 contagion of example would not fail to act on every favorable 

 occasion, at least as long as old birds were present. . . . 



" It may be asked in this connection how the various species 

 which start together or join one another during the early stages 

 of their journey separate again, as must be the case, when 

 they reach a point beyond which their routes diverge. An 

 answer to this was suggested at Point Lepreaux by the fact 

 that, while many species of birds arrived together on the same 

 night, and mingled indiscriminately in the neighboring woods 

 during the following day, they did not invariably depart to- 

 gether or in exactly the same direction. This leads me to 

 believe that similar places along every route constitute what 

 may be called stations or points of departure. At such places 

 ordinarily promontories extending into the sea, points of tim- 

 ber bordering extensive plains, or the extremities of mountain 

 ranges the migratory tide hesitates and halts before ventur- 

 ing on the dangerous stage ahead, and (as we know to be the 



