Page:Popular Science Monthly Volume 77.djvu/102

96 study of their habits gives no support to the idea advanced by Darwin, in his "Origin of Species," that they are passing along the same road to parasitism already traversed by their European relative. I do not know whether the American cuckoos ever built a better nest or not, but it is certain that the present structure is adequate to their needs, and affords no evidence of a waning instinct of nidification. (4) The final stage of the parasitic instinct among the Cuculidæ is presented by their famous European representative, Cuculus canorus, in which the instincts of both young and adult have become so specialized that to describe them at all adequately would require many pages. One hundred and nineteen different species of birds have been the prey of this parasite, the eggs of which have become reduced in size and highly variable in form and color. The commonest dupes are birds of small size, like the hedge sparrow and titlark; but one egg is laid in the same nest by the same bird, and this is often similar in size and coloring to those of the prospective nurse. The egg is deposited stealthily in the stolen nest, and in the absence of the owner, either just before or just after the proper eggs have appeared, or it is first dropped on the ground and conveyed to the nest in bill or gullet, by which the range of accessible nests is greatly increased. These and other remarkable practises of this bird have been fully described in a paper on the "Life and Instincts of the Cuckoo," shortly to appear.

All travelers who have studied the ostriches of South America and Africa in the field speak of the great numbers of their eggs which are annually wasted both in and out of season by dropping them over the plains or around their nests. If this is a secondary character, it must have come from a disturbance of the normal cycle, quite similar to what we have found in cuckoos and starlings. In this case adjustment seems to have been effected in quite a different manner, for we find the male taking upon himself almost the whole duty of incubation and care of the young. Even the wasted eggs, at least in the neighborhood of the nest, serve a secondary use as food, for the young soon break them open and devour them.

We can not discuss with much profit the remarkable breeding habits of the megapodes of Australia and the East Indies, referred to earlier in this paper, until naturalists have made more detailed studies upon the various species. The notes which follow are purely tentative, and are offered by way of suggestion. The true megapodes build huge mounds of earth and leaves, which serve as incubators for their eggs, and the young, which may or may not be subsequently tended by their parents, are in most cases able to run or fly from birth, or when they emerge from their mound. The moleos or "maleos" deposit theirs in black volcanic sand which is both clamp and warm, either by the seashore or in the vicinity of warm springs in the interior. In any case