254 A THEORY OF BIRDS' 2fESTS f 



that this is only an apparent exception, for almost all 

 the bright colours are on the under surface, the back 

 being usually olive green or brown, and the head black, 

 with brown or whitish stripes, all which colours would 

 harmonize with the foliage, sticks, and roots which 

 surround the nest, built on or near the ground, and 

 thus serve as a protection to the female bird. 



4. Grallina Australis. This Australian bird is of 

 strongly contrasted black and white colours. The sexes 

 are exactly alike, and it builds an open clay nest in 

 an exposed situation on a tree. This appears to be 

 a most striking exception, 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 con- 

 spicuous. It has been remarked that small patches 

 of w r hite and black blend at a short distance to form 

 grey, one of the commonest tints of natural objects. 



5. Sunbirds (Nectarineidse). In these beautiful 

 little birds the males only are adorned with brilliant 

 colours, the females being quite plain, yet they build 

 covered nests in all the cases in which 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 prevent the 

 female acquiring the gay colours of her mate, and 

 there is one curious circumstance which tends to 

 elucidate it The male of Leptocoma zeylanica is said 



