A NATURALIST IN BRAZIL 



only by chance, because it opened its great eyes as I approached it 

 too closely. The nightjars, known as Bacaraus in Brazil, may be 

 recognized by their silent but characteristic flight, their long forked 

 tails, and the white crescent on the throat, or by their singular 

 rrrrr, which can be heard at a great distance. By day they press 

 themselves close against the trunk of a tree, or lie at the end of 

 a dead branch, when they so closely resemble the bark that even 

 the larger species may escape detection. Their plumage is marked 

 with the minutest detail ; the bark of a tree is scrupulously imitated 

 by its fine streaks and spots as though the bird had been held beside 

 a piece of bark and coloured to resemble it, streak by streak, with 

 a fine brush. But here the appearance of the bird when seen from a 

 short distance has to be considered. A hawk swooping past the 

 bough on which the nightjar is crouching, a panther clambering 

 past it, must be deceived in spite of its proximity. 



But there are times when the diurnal birds too sit still for hours 

 at a time, and at such times they have need of special protection, 

 since these times occur at their breeding-season, and if they were 

 detected by their enemies not only their own lives would be lost, 

 but also their eggs and their helpless young. For this reason those 

 birds have the most effectual protective coloration which nest on 

 or near the ground, where their enemies, thirsting for their blood, 

 or their eggs, are most numerous; for these do not consist only of 

 mammals, but of snakes and lizards also, and in particular the great 

 Teju lizard. Not only the Inhambus, but many of the Ant-birds are 

 for this reason covered with an inconspicuous brown pattern. 



In the case of other birds, such as the blue Kotingas, the Pipras, 

 the Gaturamos, the blue, humming-bird-like Sahys (Plate 28, i) 

 and the Humming-birds themselves, the hen bird attends to the 

 duties of incubation, and her plumage is therefore an inconspicuous 

 greenish brown, or some other neutral colour, so that she is hardly 

 visible when on the nest. The male bird, therefore, bears the species- 

 or recognition-marks for both sexes, and in a doubly conspicuous 

 form, and this makes for the preservation of the species, since its 

 enemies are more likely to capture the conspicuous males, which 

 throughout the animal kingdom are almost always in the majority, 

 so that their decimation does less damage to the species than that 

 of the females, whose loss would mean the loss of their brood. Some 

 writers have even spoken of "the sacrifice of the males" ; but the 

 sacrifice, of course, is not deliberate but enforced. 



In the case of birds of which both sexes display conspicuous 

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