OTES 



THE MEANING OF BIRDS' SONGS. 

 If I read him correctly, Mr. F. Stubbs (antea, p. 155) seems 

 to think that song is nothing more than the ebullition of 

 superfluous energy. That is to say that it plays as much or 

 as little part in the life of a bird as the steam escaping into 

 the air from the safety-valve of an overcharged boiler plays in 

 regard to the economy of an engine. Mr. Kirkman boldly 

 says, that a Robin " sings to please himself " But do we in 

 Nature see things running to waste in this spendthrift way ? 



When Mr. Stubbs says in regard to singing that the bird 

 has " no alternative," I suppose no one will disagree with him, 

 for song is surely an " unconscious," almost a reflex act, 

 initiated by a series of internal physiological changes and 

 external conditions in the environment of the bird. Of course, 

 if we choose to think that any vitality can be superfluous, I 

 suppose we may say, with Mr. Stubbs, that song is the result 

 of superfluous vitality. But then we can just as easily say 

 the same of reproduction, which does not seem to get us much 

 further. 



What we should like to know is, what is this " vitality," 

 and in what mysterious way is it induced to act in certain 

 directions at certain cyclical periods. Mere abundance of food 

 does not seem a sufficient explanation, otherwise we should 

 have expected the song of the Blackcap to have waxed 

 stronger in the spring, which was not the case. 



Has anyone ever compared the syrinx of a bird during the 

 reproductive period with that of a syrinx in the non-breeding 

 or nestling stage ? We know that at certain periodic seasons 

 the reproductive organs take on an increased physiological 

 and histological activity and are thus ready to perform their 

 functions if the opportunity arises. We know also that in 

 the case of the higher vertebrates, distant organs and tissues 

 of the body become physiologically active in sympathy with 

 and synchronously with the physiological activity of the 

 reproductive organs, and it is not difficult to imagine that in 

 birds the syrinx may behave in the same sympathetic way, 

 becoming more adapted at this period for the utterance of 

 finer notes, this sympathetic action being really due to an 

 internal secretion which perhaps has, at the same time, a 

 selective action on other tissues. Supposing this were so 

 song would become a purely sexual phenomenon. 



