Of all bird-habits, probably none has excited more interest than the manner of life of the young cuckoo. Its parents build no nest, but [Pg 325] depend entirely upon other birds for rearing their offspring. The female cuckoo lays her egg upon the ground and then carries it in her bill to a nest which contains similarly coloured eggs, if such a nest is to be found. If not, another convenient nest is selected. It is said that the male sometimes renders assistance by distracting the attention of the rightful owners in the meantime. In most cases the owners of the nest, apparently unaware of the trick, sit upon the strange egg with the rest, and in due course the young birds are hatched. The young cuckoo, whilst still blind and naked, wriggles itself under its foster brothers and hoists them over the edge of the nest. Far from resenting the crime, the duped parents now devote their energies to feeding the murderer, and continue their attentions until after it is fully fledged (about a fortnight after hatching) and perhaps several times their combined size. Fig. 211.—Cuckoo’s Egg in Greenfinch’s Nest (Cuckoo’s Egg on the right). The small size of the cuckoo’s egg—about one-fourth of what might be [Pg 326] expected from so large a bird—and its general similarity in colour to their own eggs, both aid in deceiving the victimised birds in the first instance, and the disproportionate size of their supposed offspring shortly after hatching apparently does not arouse their suspicions. It is believed that any particular female cuckoo lays only eggs of one type and deposits them, as far as possible, in nests of the mimicked species—the species, probably, by which she herself was reared. During the summer, therefore, she visits one such nest after another, until she has disposed of all her eggs. Further, it is supposed that her offspring inherit her tendency to lay eggs of the particular colour, and therefore to prey in their turn upon the species of their foster-parents. In this country, the meadow pipit, pied wagtail, robin, and reed-warbler are perhaps the most usual victims of the cuckoo’s parasitism, but the nests of other species (Fig. 211) are not uncommonly selected. The old cuckoos depart about the end of July, apparently leaving the young ones to find their way south alone. 58. THE DUCK.