INTRODUCTION. xxv 



conspicuous in an open nest, and those of the latter are well adapted 

 by their colour to harmonize with surrounding tints. If warmth is 

 required in the one case, certainly it should be in the other also. Again, 

 I have known the Wild Duck cover her eggs so completely as almost to 

 defy detection, and that, too, long before she had commenced to sit, and 

 when no warmth was required. I think, therefore, that there can be little 

 doubt that it is solely from motives of concealment that these conspicuous 

 eggs are covered. Stevenson, in his 'Birds of Norfolk' (ii. p. 417), also 

 confirms this opinion, and says that (in the case of the Moorhen) the pre- 

 caution of covering the eggs is more particularly adopted when the nest is 

 in an exposed situation. 



But we find many conspicuous eggs laid in bare open places that are not 

 concealed in such a cunning manner. We can take as an instance the 

 Short-eared Owl, who lays her white eggs on the open fens and marshes, 

 or many of the Goatsuckers, who deposit their white eggs in flimsy open 

 nests, or certain Ground-Pigeons (Geophaps] of Australia, who lay their 

 bufnsh- white eggs on the bare ground. How are such eggs protected? 

 In this manner : The plumage of all these birds is remarkably protective 

 and assimilates very closely with the surroundings; moreover, they 

 possess the habit of sitting very closely, conscious that they resemble the 

 ground or branches and cannot readily be seen ; and so they brood over 

 their conspicuous eggs, shielding them by their sober plumage until 

 almost trodden upon, ere they rise from them. We might also notice 

 another rather puzzling instance belonging to this group, and that is 

 to be found amongst the Pigeons. The nests of nearly all these birds 

 are remarkably similar platforms of twigs built in trees, rocks, or on the 

 ground ; and the eggs are in all cases, so far as is known, white, or nearly 

 so, and spotless. Pigeons' nests are very slight and inconspicuous, and, as 

 a rule, built in the dense cover ; moreover, the birds themselves are exces- 

 sively wary. Again the very fact that these birds are so abundant and so 

 widely spread over the world, notwithstanding their open nests and white 

 eggs, is, in itself, strong evidence that these birds and their eggs are not 

 much exposed to enemies or are well able to elude them, and also shows 

 us how cautious we should be in looking upon such facts as serious objec- 

 tions opposed to laws of uidification and colour. As an instance .of how 

 complex this subject is, we might take the great family of the Goatsuckers. 

 Some of these birds (dLgotheles, or Owlet Nightjars of Australia) lay white 

 eggs in holes of trees ; others, as the Frog-mouths (Podargidse), build a 

 Pigeon-like nest on a branch and lay white eggs, depending for safety on 

 the protective colours of their own plumage ; whilst the true Goatsuckers, 

 of which our Common Nightjar may be taken as an example, lay eggs on 

 the bare ground of protective tints, as well as depending on the sober colours 

 of their plumage for safety. It remains now but to notice in this group 



VOL. II. c 



