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Show 168 SEXUAL SELECTION : BIRCS. PART II. nacious and could defend themselves; that those of the second group take extreme care in concealing their open nests, but this does not in:ariably hold good ; 11 and that with the birds of the thud group the females are brightly coloured chiefly on the unde~ surface: Besides these cases the whole great fam1ly of p1geons, which are sometimes brightly, and almost always conspicuously coloured, and which are notori?usly liable. to the attacks of birds of prey, offers a serwus exceptiOn to tho 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 brmiant than the males, are very brightly coloured. Nor can it be maintained that all female hummingbirds, which are brightly coloured, escape J etection by their tints being green, for some display on their upper -surfaces red, blue, and other colours.12 In regard to birds which build in holes or construct domed nests, other advantage~, as Mr. Wallace remarks, besides concealment are gained, such as shelter from the rain, greater warmth, and in hot countries protection from the rays of the sun ;13 so that it is no valid u Jordon, 'Birds of Indin,' vol. ii. p. 108. Gould's' Handbook of tho Birds of Australia,' vol. i. p. 4G3. 12 For instance, tho female Eupetomena mnc1·oura has tho head and tail dork blue with reddish loins; the femole Lampornis porpltyru1·us is blackish-green on the upper surface, with tho loros and sid<;s of tho throat crimson ; tho female Eulampis jugularis hns the top of tho head anu back green, but the loins and the tail nre crimson. Many other instances of highly conspicuous females could be given. See Mr. Gould's mao-nificent work on this family. ~~ Mr. Salvin noticed in Guatemala ('Ibi s,' 18Gt, p. 375) that hummin< Y-bi:rds were much more unwilling to leave their nests during very hot ~vcather, when the sun was shining brightly, tl1an during cool, cloudy, or rainy weather. CJJAP. XY. COLOUR AND NIDIFICATION. 169 .objection to his view that many birds having both sexes obscurely coloured build concealed nests.14 rrhe female Horn-l>ills (Buceros), for instance, of India and Africa are protected, during nidification, with extraordinary care, for the male plaisters up the hole in which the female sits on her eggs, and leaves only a small orifice through which he feeds her; she is thus kept a close prisoner during the whole period of incubation; 15 yet female ho1·nbills are not more conspicuously coloured .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 coloured and the females obscure, .and yet the latter hatch their eggs in domed nests. This is the case with the Grallinre of Australia, the Superb Warblers (Maluridro) of the same country, ihe Sun-birds (Nectarinire), and with several of the Australian Honey-suckers or Meliphagidre.1G If we look to the birds of England we shall see that there is no close and general relation between tho .colours of the female and the nature of the nest constructed by her. About forty of our British birds (exdueling those of large size which could defend themselves) build in holes in banks, rocks, or trees, or construct domed nests. If we take the colours of the female goldfinch, bullfinch, 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 considered 14 I may specify, as instances of obscurely-coloured birds building conce.aled ~csts, the species belonging to eight Austmlian genera, descr1bed m Gould's 'Handbook of the Birds of Australia,' val. i. p. 340, 362, 365, 383, 387, 389, 391, 414. 15 Jerden, 'Birds of India,' val. i. p. 244. 16 On the nidification and colours of these latter species sec Gould's ·'Handbook,' &c., vol. i. p. 504, 527. ' |