Page:The British Warblers A History with Problems of Their Lives - 3 of 9.djvu/44

 that the males, in their great excitement, indulge in a medley of imitations of the songs and call-notes of alien species?

The fact that birds with gorgeous plumage do not as a rule possess any great powers of song, and, on the other hand, that the best singers are as a rule dull-coloured, is regarded as an indication of the reality of sexual selection, in so far as it proves that the excitement of the female has been essentially affected by only one of the characters of the male. If this were a true interpretation of the facts, which are not disputed, we should, by the same train of reasoning, expect to find that the bodily and vocal antics have been mutually exclusive, that the best singers do not, during their courtship, perform in a manner which could be interpreted as a display of plumage. But we do not do so. The best singers do perform in the most extravagant manner possible, and this seems to me to lessen the importance that is attached by the advocates of this theory to the mutual exclusiveness of gorgeous colouring and beautiful song.

The view I hold with regard to these extravagant bodily antics is that they are reflex actions directly resulting from any excessive excitement, that they are not confined solely to courtship, and do not in any way influence the female. This view, as I am inclined to believe, gains considerable support from the fact that we find a parallel case in the vocal organs, namely, that whenever the excitement reaches a certain degree of intensity, no matter how different the stimulus may be, the reactions that follow are always similar.

If you watch a pair in the evening of the same day upon which the mating has first taken place, you will notice a remarkable change. The excitement has for the time passed away; never, in fact, to return in the same degree of intensity until the following season. Instead of the restless pair that were following one another about during the first hours of daylight, you find a pair simply contented to remain in one another's company. They are often close together, very close sometimes, almost touching one another on the same branch,