86 Journal of Travel and Natural History 



IV. GralHna Australis. This Australian bird is of strongly con- 

 trasted black and white colours. The sexes are exactly 

 alike, and it builds an open clay nest in an exposed situ- 

 ation on a tree. This appears to be a most striking excep- 

 tion, but I am by no means sure that it is so. We require to 

 know what tree it usually builds on, the colour of the bark 

 or of the lichens that grow upon it, the tints of the ground, 

 or of other surrounding objects, before we can say that the 

 bird, when sitting on its nest, is really conspicuous. It has 

 been remarked that small patches of white and black blend 

 at a short distance to form grey, one of the commonest 

 tints of natural objects. 



V. Sunbirds (Nectarineidte). In these beautiful little birds the 



males only are adorned with brilliant colours, the females 

 being quite plain, yet they build covered nests in the few 

 cases in whicli the nidification is known. This is a negative 

 rather than a positive exception to the rule, since there may 

 be other causes besides the need for protection which pre- 

 vents the female acquiring the gay colours of her mate. 

 In this case, too, the facts are very imperfectly known, and 

 there is one curious circumstance which tends to elucidate 

 it. The male of Leptocoma zeylanica is said to assist in in- 

 cubation. It is possible, therefore, that the group may ori- 

 ginally have used open nests (which, for all we know, may 

 still be the case in many species), and some change of con- 

 ditions, leading the male bird to sit, may have been followed 

 by the adoption of a domed nest. 



VI. Superb warblers (Maluridre). The males of these little 

 birds are adorned with the most gorgeous colours, while the 

 females are very plain, yet they make domed nests. It is 

 to be observed, however, that the male plumage is nuptial 

 merely, and is retained for a very short time ; the rest of the 

 year both sexes are plain a1 ike. It is probable, therefore, that 

 the domed nest is for the protection of these delicate little 

 Ijirds against the rain, and that there is some unknown cause 

 which has led to the development of colour in the males only. 



I think I have now noticed all exceptions of any importance to 

 the law of dependence of sexual colour on nidification. It will be 

 seen that they are very few in number, compared with those which 

 support the generalization ; and in several cases there are cir- 



