Page:The British Warblers A History with Problems of Their Lives - 3 of 9.djvu/59

 song, such as it is, is more of a warble than a song, through which the real notes can occasionally be traced.

While resting they sit in their characteristic attitude, like a ball of feathers, tails drooping, backs very much rounded, and their head feathers raised. After resting thus for a while they fly to the berries, and, swallowing some, compose themselves for a further repose. I have noticed that about six of these berries are generally sufficient to appease their appetites for a time, but their visits to the trees are frequent, and their digestive powers rapid. As long as an observer remains perfectly still in his retreat, they, like all other wild creatures, take little notice of him; they will only come and look from the opposite side of a branch, disappear, and return again, as if unable to understand his presence; any movement, however, no matter how slight, is sufficient to arouse their suspicions, and cause them to utter their alarm-note, when all within hearing will be on the alert.

I have already referred to the song and powers of imitation of both adult and immature birds, but since their vocal powers are so highly developed, the subject becomes a more than usually interesting one. I shall therefore relate the various phenomena I have noticed in connection with it somewhat minutely. In order to do this. I propose to divide the subject into four parts, and deal with each part separately:—
 * (1) The development in the male from year to year.
 * (2) The deterioration in both mature and immature individuals immediately coition has taken place.
 * (3) Power of imitation.
 * (4) Evidence of emulation.

(1) It will be found that in the spring, when the males first arrive, there is a great variation in the quality of the song of the different individuals, that in some cases there is a marked inferiority, which is difficult to describe but easy to detect, while in others the song is so strikingly beautiful as to at once arrest attention. The difference between these two extremes lies principally in the purer notes, which might well