The great force with which a bird grasps its perch is worthy of note. As every hawker is aware, a falcon, when carried on the wrist, grips the leather gauntlet so tightly as to almost stop the circulation of the blood in the hand of the carrier. A fox cannot open its mouth when once its snout is in the iron grip of an eagle. Examples of the power of the grip of the foot of a passerine bird will occur to every one who has had much to do with our feathered friends. Crows habitually roost in the topmost branches of trees, which must be very violently shaken in a gale of wind; yet the birds never seem to lose their hold.
I have said that the habits of the spotted munia are those of the amadavat; what was said of the latter applies to the former, with one exception. The spotted munia is no songster. Those who keep the bird must have seen him go through all the motions of singing, with a considerable display of energy, but scarcely a sound seems to issue. You may perhaps hear the feeblest noise, like that made by a wheezy and decrepit mosquito. When you see the bird’s mandibles moving nineteen to the dozen with scarcely a sound issuing, you are inclined to think that he is either playing dumb crambo or that he has taken leave of his senses. Nothing of the kind. The bird is singing his top notes, which are doubtless greatly appreciated by his mate. Sound is, as we all know in this scientific age, vibration appreciable to the ear. Air is the usual vibrating medium. Only certain vibrations are perceptible to the human auditory organ. Those having a recurrence of below thirty or above sixteen thousand per second do not produce the sensation of sound to the average human ear. There are thus numbers of vibrations continually going on which are lost to us; to this category belong the vibrations in the air produced by the vocal cords of the spotted munia. The ear of a bird is constituted very differently from that of man, so that it is not surprising if birds can hear certain sounds imperceptible to us human beings. I may here say that the range of the human ear varies greatly in different individuals. Some men can hear vibrations of which the recurrence is but fifteen in the second, while others are said to appreciate notes caused by forty thousand vibrations per second. I have a friend who cannot hear a black partridge when it is calling; its notes are too high for the unusually limited range of his ear. I do not know if there are any people to whom the note of the nutmeg bird sounds quite loud; if there be, and these lines meet their eye, I hope they will give their brethren of more limited capacity the benefit of their experience.