864 



OSTRICH. 



provision which nature has made for protecting the 

 eggs of most animals which breed on the ground. 

 There is no parade of a nest, and the eggs so much 

 resemble in colour the surface around them, that even 

 on the dry sand of a sea-beach it is very possible that 

 the first notice one has of them may be the sound of 

 breaking them under the foot. 



The time required for hatching the eggs of the 

 ostrich is not known with any degree of accuracy, 

 though it has been said that it requires between forty 

 and fifty days, and rather more in moderate climates, 

 and when the weather is wet, than in the dry heat on 

 the margins of the desert. That it must require a 

 considerable time is obvious, on account of the size 

 of the egg and the hardness of the shell, and also of 

 the degree of maturity at which the young have 

 arrived when they make their appearance. Other 

 circumstances being similar, eggs are the sooner 

 hatched the less perfectly developed the young are 

 when they break the shell. The shortest incubations 

 are those in which the young birds appear quite 

 naked, and incapable of using either the feet or the 

 wings ; and it is worthy of remark, that warm nests 

 are always provided for birds of this kind ; and they 

 of course require to be fed by the parent birds for a 

 much longer time than those which are more matured 

 on their first appearance. Where the young come 

 into the world in this comparatively rudimental state, 

 two portions of the labour of the parent birds are 

 greater than in other cases, namely, the construction 

 of the nest and the feeding of the young. The 

 abridgment of the time of sitting is, however, some 

 compensation for this ; and the warm nest no doubt 

 tends to this abridgment. 



There are other circumstances connected with 

 those birds which have callow young, which are 

 worthy of attention. In the first place, they are almost 

 all small birds ; for the large ones, almost without 

 exception, have rude nests, or no nests at all ; and 

 their young are covered with down or with feathers 

 at the time of their exclusion ; and in every instance 

 they are then capable of using their feet, while many 

 of them can immediately find their own food, inde- 

 pendently of the mother. In the second place, the 

 birds under consideration generally have their nests 

 where food is abundant, as in woods, thickets, hedges, 

 and other rich places, where insects and other small 

 animals are abundant ; and the young are exclusively, 

 in most of the species, and in the greater part in all 

 of them, fed upon those animal substances. Thirdly, 

 the season of the year at which those birds have their 

 young in the nest is the season in which the larvae of 

 insects come upon vegetation, upon that of the sweet- 

 juiced trees especially, in those myriads, and with 

 that voracious appetite, which would actually destroy 

 the vegetation of the year, were it not for the count- 

 less thousands which those birds consume for their 

 own food and for that of their young. We see, there- 

 fore, how finely the economy of these birds is adapted 

 for the general good of the whole system of nature. 

 It may seem that rooks, and many of the larger om- 

 nivorous birds which build nests in trees, form an 

 exception to what has been stated. But their nests, 

 though they often require a good deal of labour in 

 the construction, and though the young are fed in 

 them for a considerable time, are never so elaborate 

 or so warm as those of the small birds. The habits 

 of the birds too are intermediate. Their charge is 

 the ground lame and other small animals, and the 



eggs of other birds ; and this intermediate sort of 

 occupation corresponds with the intermediate style of 

 the economy of their nests. 



Many of the birds which build no regular nests, 

 and whose young appear in an advanced state, are to 

 a certain extent omnivorous ; and many of them feed 

 chiefly upon small ground animals. There is, how- 

 ever, in all cases a great degree of labour requisite 

 for the finding of their food'; and their exemption 

 from the labour of nest-building, and that of bringing 

 food for their nestlings, is the compensation which 

 nature allows them for the severe task imposed upon 

 them in supporting themselves individually. 



As the ostrich constructs no nest whatever, and is 

 in some places in a great measure exempted from the 

 labour of incubation, we might naturally expect that 

 the young should be provided for in the egg, until, 

 under average circumstances, they should be able to 

 find their own food when they come out of it. This 

 is found to be the case, and not only so, but there is 

 a very remarkable correspondence between the labour 

 of incubation, which the female ostrich performs, and 

 the care she takes of her young after they make their 

 appearance. If she requires to sit little or none, then 

 she abandons the young, and leaves them to provide 

 for themselves ; but if she requires to sit pretty con- 

 stantly, she takes them under her protection, leads 

 them to their pastures, and guards and defends them 

 with as much boldness and solicitude as a common 

 domestic hen. Thus, in the temperate climate of the 

 Cape, and especially during the rainy season, which 

 is the season of food, and therefore the season of 

 reproduction for the ostriches there, the female bird 

 is an attentive mother ; whereas, on the burning sands 

 nearer the equator, she pays little or no attention to 

 her offspring. Whether, under these different cir- 

 cumstances, there is any difference of maturity in the 

 young is a fact upon which we have no direct infor- 

 mation ; but the analogy would lead us to suppose 

 that such a difference really exists. In that part of 

 it which our information does reach, we have a strik- 

 ing instance of the modification of the same bird, so 

 as to adapt it to differences of external circumstances. 

 Where the ostrich sits closely and tends her young 

 assiduously, there is an abundant supply of food for 

 both, and they can satisfy themselves with compara- 

 tively little labour. It is then too that the young 

 stand in need of protection, because the same rich- 

 ness of the pastures which feeds the ostriches feeds 

 their enemies, if not directly, at least through the 

 medium of the herbivorous mammalia. In the burn- 

 ing deserts again, where the labour is great, the 

 ostriches are in a great measure alone ; and, though 

 the labour of finding their food is great, they are 

 exempt from the danger of almost every enemy. 



We have entered somewhat largely into those 

 points of the economy of ostriches for various reasons. 

 First, because the birds are in themselves among the 

 most interesting, not of the feathered race merely, but 

 of all animals ; secondly, because those points have 

 been slightly touched upon by some, and much mis- 

 represented by others ; and thirdly, because, from 

 their geographical position, the ostriches may be said 

 to occupy the centre or extreme place of the sun's 

 action upon the earth; and therefore their history 

 well understood may be made a most extensive and 

 valuable index to the general economy of nature on 

 the surface of our globe. 



We have already alluded to the locomotive powers 



