In spite of its large size, the rhea is not a conspicuous bird in a wild state, the grey plumage harmonising perfectly with the surrounding pampas.
Darwin, in his "Voyage of the Beagle," tells us that when he was "at Bahia Blanca, in the months of September and October, the eggs, in extraordinary numbers, were found all over the country. They lie either scattered and single, in which case they are never hatched, and are called by the Spaniards huachos; or they are collected together into a shallow excavation which forms the nest. Out of the four nests which I saw, three contained twenty-two eggs each, and the fourth twenty-seven. In one day's hunting on horseback sixty-four eggs were found: forty-four of these were in two nests, and the remaining twenty scattered huachos. The Gauchos unanimously affirm—and there is no reason to doubt their statement—that the male bird alone hatches the eggs, and for some time afterwards accompanies the young. The cock, when on the nest, lies very close: I have myself almost ridden over one. It is asserted that at such times they are occasionally fierce and even dangerous, and that they have been known to attack a man on horseback, trying to kick and leap on him. My informer pointed out to me an old man whom he had seen much terrified by one chasing him.... I understand that the male emu in the Zoological Gardens takes charge of the nest: this habit, therefore, is common to the family.
Photo by the Duchess of Bedford] [Woburn Abbey.
WHITE RHEAS.
These are only varieties of the common form, not a distinct breed.
"The Gauchos unanimously affirm that several females lay in one nest. I have been positively told that four or five hen birds have been watched to go, in the middle of the day, one after another, to the same nest.... Although this habit at first appears very strange, I think the cause may be explained in a simple manner. The number of eggs in the nest varies from twenty to forty, and even fifty; and according to Azara even seventy or eighty. Now, although it is most probable, from the number of the eggs found in one district being so extraordinarily great in proportion to the parent birds, and likewise from the state of the ovarium of the hen, that she may, in the course of the season, lay a large number, yet the time required must be very long.... If the hen was obliged to hatch her own eggs before the last was laid, the first probably would be addled; but if each laid a few eggs at successive periods in different nests, and several hens ... combined together, then the eggs in one collection would be nearly of the same age. If the number of eggs in one of these nests is, as I believe, not greater on an average than the number laid by one female in the season, then there must be as many nests as females, and each cock bird will have its fair share of the labour of incubation; and that during a period when the females probably could not sit, from not having finished laying. I have before mentioned the great number of huachos, or deserted eggs; and that in one day's hunting twenty were found in this state. It appears odd that so many should be wasted. Does it not arise from the difficulty of several females associating together, and finding a male ready to undertake the office of incubation? It is obvious that there must at first be some degree of association between at least two females, otherwise the eggs would remain scattered over the wide plains, at distances far too great to allow of the male collecting them into one nest: some ... have believed that the scattered eggs were deposited for the young birds to feed on. This can hardly be the case ... because huachos, although often found addled and putrid, are generally whole."
The Ostrich.
The Ostrich is the giant amongst living birds, the full-grown male standing some 8 feet high, and weighing about 300 lbs. It is flightless, the wings being smaller, in proportion to the size of the body, than in the rhea. But the energy which in other birds is employed in sustaining flight in the ostrich is expended in running, so that it has reached a high degree of speed—no less, in fact, than twenty-six miles an hour. When at full speed, it is generally believed the ostrich derives no small help from the wings, which are used sail-wise. Nor is this belief by any means a modern one, for all of us must be familiar with Job's observations on this subject: "What time she lifteth up her wings on high, she scorneth the horse and his rider." The wings are never used in running at full speed, but are of much service in turning, "enabling the bird to double abruptly, even when going at top speed." In justice to the older observers, however, it must be remarked that ostriches do run with raised wings, but only at the commencement of the run, or in covering a short distance, when the pace may be considerable; but if circumstances demand "full speed ahead," they are held close to the body, where they offer the least resistance to speed.
