tory. It is elaborated from pre-existing elements, and is in no wise conceivable as in itself an original form of utterance.
The above considerations cannot pass through the mind without bringing in their wake the question: Is there any useful purpose served in this fact of song elaboration? Does it get the bird anything it lacked before? Is an essentially songless bird a loser in the give and take of avian existence?
Witchell makes certain observations (p. 177) suggesting the possibility that in the strict social economy of bird life the elaborating tendency may be somewhat counteracted by some necessity of preserving the specific identity of both calls and songs for reasons of practical convenience. The calls certainly, and the songs almost as certainly, might lose their usefulness in a social sense if modified at the whims of individuals. But evidently individual modifications are not passed on and therefore do not become of racial importance. The slowness of organic evolution makes it plain that there must be deep-seated in birds, as in the rest of nature, an instinctive obedience to some principle of conservative action.
But just as plainly there is an instinctive recognition of the necessity of progress. That must explain why individuals get "freakish". But their freakishness avails the race nothing unless they get that way in groups, following a racial behavior pattern. It is a truism to say that life—including vocal bird life—implies within itself the need for growth, advancement. But even that does not satisfactorily explain why a bird improves its song: it merely says that he does because he does. Now, the following, I admit, is a theory. Given the primal necessity for song improvement, existing merely because the bird is alive, I believe that it carries with it and confers upon the bird, as a result of itself, some appreciation of itself. The bird, in other words, somewhat appreciates the work which it finds itself to have done in the line of song improvement. It is not unaware of its achievement, and is "interested" or "pleased" or even "elated". On what grounds? Because it feels the results to be useful or practical? I doubt it. Because it feels them to be pleasing—that's all. Insofar as vocal bird life is concerned, I cannot help believing that we are concerned with what Lloyd Morgan has called (p. 270) "the germs of aesthetics". In his lowly way—on his "perceptual" rather than "ideational" plane of mental development—why should not a bird, in his leisure moments and under the spell of the mating season, feel an impulse to outdo himself in song—an impulse heightened by his realization of results spontaneously achieved by mere virtue of living? I believe that herein lies the explanation of the evolution of bird song. The songster is an esthete. I shall say more of this beyond.
2. The fact of elaboration through imitation.—Upon analysis of the situation it becomes apparent that bird song can be elaborated in no other way than through imitation. The "mimetic origin of bird song" (see Rhoads, 1889) is not only the reasonable, but the inevitable origin—only we must here guard against understanding "origin" to be a synonym of "cause". Mimicry is certainly not the cause of song-development: it is the method employed—the only method, in the nature of things, available. Elaboration is imitation; though in many cases songs that we consider "original" may have been in reality copied from singers that have ceased to exist in the age and environment of the imitator (see Witchell, p. 227). It is, after all, quite natural that a species, working out its song through its individuals, should seize upon and utilize the notes of
