^°'l9i^"^] Tyler, Call-notes of Migrating Birds. 135 



important use of the call-notes is to express the feeling of migration 

 and spread it, so that other birds may catch the contagion. In 

 other words, we must not assume that a bird utters its migration 

 calls with a definite purpose either of guiding its companions or 

 of inquiring their whereabouts. Both of these results, however, 

 are doubtless accomplished by involuntary utterances excited by 

 the restlessness which culminates in migration. In any case there 

 would be as much occasion for the notes which accomplish these 

 results at the very start of migration, or even before the start, as 

 at the subsequent steps of the journey. 



It is possible that the migration calls are largely uttered by young 

 birds and take their origin from the first note which the nestling 

 makes, — the food-call. It is an easy transition from the food-call 

 of the nestling to the call which the fledgling utters to inform his 

 parents where to find and feed him, and this call, modified somewhat 

 as the fledgling grows older, might well persist as an expression of 

 enlotion and become finally the migration call. 



Some time in the second week of August, a new note makes its 

 appearance, — a clear, but softly modulated, mellow whistle. 

 This note is so loud and striking that one would expect that it 

 would have attracted the notice of anyone who chanced to be out- 

 of-doors at night. But, as far as I know, none but ornithologists 

 have interested themselves in the sound. 



For a long time this call-note remained a mystery to Mr. Faxon 

 and Mr. Brewster, until finally Mr. Brewster, by a most fortunate 

 chance, solved the problem. He was lying at dawn in his cabin 

 on the shore of the Concord river, when he heard, far in the dis- 

 tance, the familiar whistle of the unknown migrant. The bird, still 

 calling, flew nearer and nearer until it alighted in the shrubbery 

 close by the cabin. Here it continued to call, but gradually changed 

 the character of the note until, little by little, it grew to resemble, 

 and finally became the familiar call of the Veery. This observa- 

 tion proves beyond any doubt that the Veery is the author of one 

 of the whistles which we hear in the night during the times of migra- 

 tion and that the Veery's migration call is quite distinct from its 

 notes heard commonly in the daytime. I should add that a small 

 number of these calls (perhaps one per cent.) are identical with the 

 Veery's diurnal "wheeoo" call. 



One other observer has published some evidence on this subject. 



