SEXUAL SELECTION 585 



open and exposed nests. In another large family, that of 

 the humming-birds, all the species build open nests, yet 

 with some of the most gorgeous species the sexes are alike; 

 and in the majority, the females, though less brilliant than 

 the males, are brightly colored. Nor can it be maintained 

 that all female humming-birds, which are brightly colored, 

 escape detection by their tints being green, for some display 

 on their upper surfaces red, blue, and other colors." 



In regard to birds which build in holes or construct 

 domed nests, other advantages, as Mr. "Wallace remarks, 

 besides concealment 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 con- 

 cealed nests." The female Horn-bill {Buceros), for instance, 

 of India and Africa is protected during incubation with 

 extraordinary care, for she plasters up with her own excre- 

 ment the orihce 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 brilliantly colored and the females 

 obscure, and yet the latter hatch their eggs in domed nests. 



" For instance, the female Eapetomena macrowra has the head and tail 

 dark blue with reddish loins; the female Lampornis porphyrwus is blackish 

 green on the upper surface, with the lores and sides of the throat crimson; 

 the female Eulampis jugula/ria has the top of the head and back green, but the 

 loins and the tail are crimson. Many other instances of highly conspicuous 

 females could be given. See Mr. Gould's magnificent work on this family. 



'■' Mr. Salvin noticed in Guatemala ("Ibis," 1864, p. 315) 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. 



" I may specify, as instances of duU-colored birds building concealed nests, 

 the species belonging to eight Australian genera, described in Oould's "Hand- 

 book of the Birds of Australia," vol. i. pp. 340, 362, 365, 383, 387, 389, 

 391, 414. 



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



