These are thirteen sounds forcing themselves incessantly upon the Brown Towhee's attention. It is reasonable to assume, then? that they are the sounds most in line for imitation. The question is: Why is the House Wren's song the sound chosen?
"One of the most extraordinary facts of our life," declares William James (p. 217), "is that, although we are besieged at every moment by impressions from our whole sensory surface, we notice so very small a part of them. The sum total of our impressions never enters into our experience, consciously so called, which runs through the sum total like a tiny rill through a broad flowery mead. Yet the physical impressions which do not count are there as much as those that do, and affect our sense organs just as energetically. Why they fail to pierce the mind is a mystery …".
This was written concerning human experience, but I do not see why it is not just as applicable to bird experience. The factor of attention certainly enters into the situation. The Towhee "just naturally" attends to certain sounds and disregards others. As between a dozen sounds equally thrust upon his ears, he is for some reason interested in certain ones more than others, and therefore all the others are shut out of his conscious consideration.
To quote from Lloyd Morgan: "We often say … that interest guides behavior in this direction or in that. But such interest must not be regarded as an impelling force; it is an attribute of the conscious situation, more or less suffused with feeling-tone. It is not easy to define; but it seems to take on its distinctive character when representative elements contribute what Dr. Stout terms 'meaning' to the conscious situation".
When a Brown Towhee (acting for and in accordance with its race, due to the identity of germ-plasm in all members) selects the song of a House Wren rather than any one of the other eleven sounds equally forced upon its sense of hearing, the song of the House Wren must have some special meaning over and above the other sounds. Let me ask even again: Has this meaning anything to do with the social economy of Brown Towhee life? Is it a matter of life and death that certain types of sound shall be shut out of the conscious attention, and others heeded? And again let me reply that I do not believe any such thing. When it is becoming so questionable that even a human being is born with anything within him that causes him? to act for the advantage of his own kind, why should we expect it in birds? Human beings show "interests" in things, but these interests are commonly in no way connected with race progress and are not even vital to the individual. I mean, it makes no killing difference if a wavering boy finally chooses radio operating instead of architecture. Nor does it make any more difference whether a Broom Towhoe chooses to imitate a Wren song or a Flicker call. Insofar as a choice of musical sounds is concerned it does not seem reasonable that anything is at work except a sort of taste. Human beings like and pay attention to certain musical compositions above certain others. So does the Brown Towhee. In selecting the song of the House Wren he is guided, in my opinion, by a lowly sort of aesthetic feeling. Xenos Clark believes that birds have "an ear for music" and that in evolving their songs they follow a harmonic pathway, which, however, happens to be for them the pathway of least resistance. The primitive bird, he says (p. 212), "sang to please himself or his mate, and the most pleasing combination of notes was that most easily heard; the combination producing least friction and securing the
