with their total absence among most nuts, would lead to the conclusion that their likes and dislikes in the matter of smell are fully as marked.
But it is when we arrive at the sense of hearing that we come to the point where proper æsthetic feelings begin. It is quite impossible to doubt that birds are fond of musical sounds. The song of our own nightingales and linnets, the deep notes of the South American bellbird, the incessant cooing of the dove, the noisy chattering of the parrots, the ringing cry of the whippoorwill, all lead to the same conclusion. Here, again, these sounds are of precisely the same nature as those employed by the crickets, katydids, cicadas, and other musical insects, as well as by man himself in his vocal and instrumental music. Something of the same taste is displayed among the quadrumana by the howlers and other monkeys. But it is a noteworthy fact that a large majority of these presumably sexual calls, in birds, insects, and other animals, are true musical sounds, not mere noises. I have pointed out elsewhere the probable reason for this preference of pure tones in the case of mankind; and the same argument will apply, mutatis mutandis, to all other animals. But there is certainly a singular analogy in this respect between sounds and colors, most animals preferring the relatively pure and simple musical tones to confused noises; and the relatively pure and simple analytic colors, red, blue, green, and yellow, to confused mixtures such as brown, gray, and mud-color. At any rate, a bird evidently pays far more attention to the musical class of auditory perceptions than to mere noise. A canary will take no notice of ordinary confused sounds in a room; but, if one begins to chirp or whistle to it, it immediately responds with another chirp in emulation. So, too, when a piano or other musical instrument is played in the neighborhood of a singing bird, it will often show its recognition of the musical character by pouring out its very fullest flood of song, as if to conquer its unconscious rival. Of course, the singing-matches between birds themselves are too familiarly known to call for separate mention. It may be worth while, however, to notice that this love of musical sound exists even among certain reptiles; for I have often seen the common house-lizard of Jamaica listening with evident interest and attention to the playing of a piano, turning his head from side to side, and scampering away when disturbed, only to return again to the fascinating sound after a minute or two of hesitation.
The cases of the starling, the piping bullfinch, and the mockingbird, which can be taught to whistle a tune, show the same power still more highly developed. These instances prove not merely susceptibility to musical sounds, but also a capacity for distinguishing the harmonic intervals. It is stated that some birds, even in the wild state, display considerable knowledge of the musical scale; and a San Francisco naturalist is at present engaged upon a work in which he hopes to show that the human ear possesses in this respect merely a
