'Jjiap, XV. Birds — Colour and Nidificaiiou, 453 



open nests have been specially modified for the sake of piotee- 

 tion ; but we shall presently see that there is another and more 

 probable explanation, namely, that conspicuous females have 

 acquired the instinct of building domed nests oftener than dull- 

 coloured birds. Mr. Wallace admits that there are, as might 

 have been expected, some exceptions to his two rules, but it is a 

 question whether the exceptions are not so numerous as seriously 

 to invalidate them. 



There is in the first place much truth in the Duke of Argyll's 

 remark 10 that a large domed nest is more conspicuous to an 

 enemy, especially to all tree-haunting carnivorous animals, than 

 a smaller open nest. Nor must we forget that with many birds 

 which build open nests, the male sits on the eggs and aids the 

 female in feeding the young : this is the case, for instance, with 

 Pyranga <xstiv<t, n one of the most splendid birds in the United 

 States, the male being vermilion, and the female light brownish- 

 green. Now if brilliant colours had been extremely dangerous 

 to birds whilst sitting on their open nests, the males in these 

 cases would have suffered greatly. It might, however, be of 

 such paramount importance to the male to be brilliantly coloured, 

 in order to beat his rivals, that this may have more than com- 

 pensated some additional danger. 



Mr. Wallace admits that with the King-crows (Dicrurus), 

 Orioles, and Pittidse, the females are conspicuously coloured, 

 yet build open nests ; but he urges that the birds of the first 

 group are highly pugnacious and could defend themselves ; that 

 those of the second group take extreme care in concealing tbeir 

 open nests, but this does not invariably hold good; 12 . and that 

 with the birds of the third group the females are brightly 

 coloured chiefly on the under surface. Besides these cases, 

 pigeons which are sometimes brightly, and almost always con- 

 spicuously coloured, and which are notoriously liable to the 

 attacks of birds of prey, offer a serious exception to the rule, for 

 they 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 brightly coloured. Nor can it be maintained 

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

 escape detection by their tints being green, for some display on 

 their upper surfaces red, blue, and other colours. 13 



10 'Journal of Travel,' edited by 12 Jerdon, 'Birds of India,' vol. 

 A. Murray, vol. i. 1868, p. 281. ii. p. 108. Gould's 'Handbook oi 



11 Audubon, ' Ormtnological Bio- the Birds of Australia,' vol. i. p. 463, 

 graphy,' vol. i. p. 233. 13 For instance, the female Eupe 



