286 The Naturalist in La Plata.
habitually expressed, although not infrequently with variations due to the greater intensity of the feeling. In some migrants the males arrive before the females, and no sooner have they recovered from the effects of their journey than they burst out into rapturous singing; these are not love-strains, since the females have not yet arrived, and pairing-time is perhaps a mouth distant; their singing merely expresses their overflowing gladness. The forest at that season is vocal, not only with the fine melody of the true songsters, but with hoarse cawings, piercing cries, shrill duets, noisy choruses, drummings, boomings, trills, wood-tappings--every sound with which different species express the glad impulse; and birds like the parrot that only exert their powerful voices in screamings--because "they can do no other"--then scream their loudest. When courtship begins it has in many cases the effect of increasing the beauty of the performance, giving added sweetness, verve, and brilliance to the song, and freedom and grace to the gestures and motions. But, as I have said, there are exceptions. Thus, some birds that are good melodists at other times sing in a feeble, disjointed manner during courtship. In Patagonia I found that several of the birds with good voices--one a mocking bird--were, like the robin at home, autumn and winter songsters.
The argument has been stated very binefly: but little would be gained by the mere multiplication of instances, since, however many, they would be selected instances--from a single district, it is true, while those in the Descent of Man were brought
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together from an immeasurably wider field; but the principle is the same in both cases, and to what I have written it may be objected that, if, instead of twenty-five, I had given a hundred cases, taking them as they came, they might have shown a larger proportion of instances like that of the cow-bird, in which the male has a set performance practised only during the love-season and in the presence of the female.
It is, no doubt, true that all collections of facts relating to animal life present nature to us somewhat as a "fantastic realm"--unavoidably so, in a measure, since the writing would be too bulky, or too dry, or too something inconvenient, if we did not take only the most prominent facts that come before us, remove them from their places, where alone they can be seen in their proper relations to numerous other less prominent facts, and rearrange them patch work-wise to make up our literature. But I am convinced that any student of the subject who will cast aside his books--supposing that they have not already bred a habit in his mind of seeing only "in accordance with verbal statement"--and go directly to nature to note the actions of animals for himself--actions which, in many cases, appear to lose all significance when set down in writing--the result of such independent investigation will be a conviction that conscious sexual selection on the part of the female is not the cause of music and dancing performances in birds, nor of the brighter colours and ornaments that distinguish the male. It is true that the females of some species, both in the vertebrate and insect kingdoms, do exercise a
288 The Naturalist in La Plata.