Cuckoos, then, reach these islands about the third week of April, and they leave us again at the end of the summer, the old birds flying south in July, the younger generation following three or four weeks later. Goodness knows by what extraordinary instinct these young ones know the way. But the young cuckoo is a marvel altogether in the manner of its education, since, when one comes to think of it, it has no upbringing by its own parents and cannot even learn how to cry "Cuckoo!" by example or instruction. Its foster-parents speak another language, and its own folk have ceased from singing by the time it is out of the nest. A good deal has been written about the way in which the note varies, chiefly in the direction of greater harshness and a more staccato and less sustained note, towards the end of the cuckoo's stay. According to the rustic rhyme, it changes its tune in June, which is probably poetic licence rather than the fruits of actual observation. It is, however, commonly agreed that the cuckoo is less often heard as the time of its departure draws near, and the easiest explanation of its silence, once the breeding season is ended, is that the note, being the love-call of a polygamous bird, is no longer needed. In Australia the female cuckoo is handsomely barred with white, whereas the male is uniformly black; but with our bird it is exceedingly difficult to distinguish one sex from the other on the wing, and, were it not for occasional evidence of females having been shot when actually calling, we might still believe that it is the male only that makes this sound. The note is joyous only in the poet's fancy, just as he has also read sadness into the "sobbing" of the nightingale. There is, indeed, when we consider its life, something fantastic in the hypothesis that the cuckoo can know no trouble in life, merely because it escapes the rigours of our winter. Eternal summer must be a delight, but the cuckoo has to work hard for the privilege, and it must at times be harried to the verge of desperation by the small birds that continually mob it in broad daylight. This behaviour on the part of its pertinacious little neighbours has been the occasion of much futile speculation; but the one certain result of such persecution is to make the cuckoo, along with its fellow-sufferer, the owls, preferably active in the sweet peace of the gloaming, when its puny tyrants are gone to roost. Much heated argument has raged round the real or supposed sentiment that inspires such demonstrations on the part of linnets, sparrows, chaffinches, and other determined hunters of the cuckoo. It seems impossible, when we observe the larger bird's unmistakable desire to win free of them, to attribute friendly feelings to its pursuers. Yet some writers have held the curious belief that, with lingering memories of the days when, a year ago, they devoted themselves to the ugly foster-child, the little birds still regard the stranger with affection.