448 THE DESCENT OP MAN. 



In regard to tirds which build In holes or construct domed 

 nests, other advantages, as Mr. Wallace remarks, besides con- 

 cealment are gained, such as shelter from the rain, greater 

 warmth, and in hot countries protection from the sun;" so that 

 it is no valid objection to his view that many birds having both 

 sexes obscurely colored build concealed nests.^° The female Horn- 

 bill (Buceros), for instance, of India and Africa is protected dur- 

 ing incubation with extraordinary care, for she plasters up with 

 her own excrement the orifice of the hole in which she sits on her 

 eggs, leaving only a small orifice through which the male feeds 

 her; she is thus kept a close prisoner during the whole period 

 of incubation;" yet female horn-bills are not more conspicuously 

 colored than many other birds of equal size which build open 

 nests. It is a more serious objection to Mr. Wallace's view, as is 

 admitted by him, that In some few groups the males are bril- 

 liantly colored and the females obscure, and yet the latter hatch 

 their eggs in domed nests. This is the case with the GrallinaB 

 of Australia, the Superb Warblers (Maluridae) of the same coun- 

 try, the Sun-birds (Nectariniag), and with several of the Aus- 

 tralian Honey-suckers or Meliphagidae." 



If we look to the birds of England we shall see that there is no 

 close and general relation between the colors of the female and 

 the nature of the nest which is constructed. About forty of our 

 British birds (excluding those of large size which could defend 

 themselves) build in holes in banks, rocks, or trees, or construct 

 domed nests. If we take the colors of the female goldfinch, bull- 

 finch, or blackbird, as a standard of the degree of conspicuousness, 

 which is not highly dangerous to the sitting female, then out 

 of the above forty birds, the females of only twelve can be con- 

 sidered as conspicuous to a dangerous degree, the remaining 

 twenty-eight being inconspicuous.'' Nor is there any close rela- 



" Mr. Salvin noticed in Guatemala ('Ibis,' 1864, p. 375) that humming-- 

 birds were much more unwilling to leave their nests during very hot 

 weather, when the sun was shining brightly, as if their eggs would 

 be thus injured, than during cool, cloudy, or rainy weather. 



1' I may specify, as instances of dull-colored birds building concealed 

 nests, the species belonging to eight Australian genera, described in 

 Gould's 'Handbook of the Birds of Australia," vol. i. pp. 340 362 365 

 383, 3S7, 389, 3D1, 414. ' ' 



" Mr. C. Home, 'Proc. Zoolog. Soc." 1869, p. 243. 



" On the nidiflcation and colors of these latter species, see Gould's 

 'Handbook,' &c., vol. i. pp. 504, 527. 



« I have consulted on this subject, Macgillivray's 'British Birds,' 

 and though doubts may be entertained in some cases in regard to 

 the degree of concealment of the nest, and to the degree of con- 

 spicuousness of the female, yet the following birds, which all lay 

 their eggs in holes or in domed nests, can hardly be considered, by 



