168 SEXUAL SELECTION : BIRDS. Paet IJ 



nacions and could defend themselves ; that those of the 

 second group take extreme care in concealing their 

 open nests, but this does not invariably hold good ; ^^ 

 and that with the birds of the third group the females 

 are brightly coloured chiefly on the under surface. Be- 

 sides these cases the whole great family of pigeons, 

 which are sometimes brigh.tly, and almost always con- 

 spicuously coloured, and which are notoriously liable to 

 the attacks of birds of prey, offers a serious exception 

 to the rule, for pigeons almost always build 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 very brightly coloured. 

 Kor can it be maintained that all female hummins:- 

 birds, which are brightly coloured, escape detection by 

 their tints being green, for some display on their upper 

 surfaces red, blue, and other colours.^^ 



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 protec- 

 tion from the rays of the sun ;^^ so that it is no valid 



^1 Jerdon, ' Birds of India,' vol. ii, p, 108. Gould's ' Handbook of 

 the Birds of Australia,' vol. i. p. 463. 



^2 For instance, the female Eupefomena macroura has the head and 

 tail dsrk blue with reddish loins ; the female Lampornis porphyrums 

 is blackish-green on the upper surface, with the lores and sides of the 

 throat crimson ; the female Eulampis jugularis 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. 



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

 ming-birds were much more unwilling to leave their nests during very 

 hot weather, when the sun was shining brightly, than during cool, 

 cloudy, or rainy weather. 



