114 BOMBAY DUCKS 



isolated from all other tribes. They show affinities 

 to both bee-eaters and kingfishers, especially to the 

 latter. Indeed, rollers are the terrestrial counterparts 

 of kingfishers : they are kingfishers which do not fish. 

 Both families are clothed in brilliant plumage, and 

 in each the sexes are alike. Both nest in holes, and 

 both lay white eggs. These last two characteristics, 

 however, do not count for much as evidence of re- 

 lationship, being merely the consequences of similar 

 habits. 



It is almost a law of nature that those species of which 

 both the cock and the hen bird are clothed in gay 

 plumage lay whitish eggs and either nest in holes, or 

 build covered nests. There are exceptions to the rule, 

 which cannot be dealt with in this place. The reason of 

 this general provision of nature is not far to seek. The 

 hen, when she is sitting on her eggs, is liable to be 

 attacked unawares by birds of prey; hence it is obviously 

 to the interest of the species that she be as incon- 

 spicuous as possible, unless, of course, she be a bird, like 

 our universal friend the crow, fully capable of looking 

 after herself, or like the king-crow, a real fighter. 



Thus it has come to pass that, in many species of 

 birds, the hen is clothed in sombre plumage, even when 

 the cock bird is arrayed, like Joseph of old, in a coat of 

 many colours. It is, however, obvious that if a species 

 nest in a hole, there is no necessity for the hen bird to 

 be inconspicuous, hence among kingfishers, woodpeckers, 

 rollers, and bee-eaters, which build in holes, both sexes 

 rejoice in brilliant plumage. 



Again, if a bird nest in a dark place, it is important 



