THE VICTORIAN NATURALIST. 191 



far down hollow stumps and branches, according to Mr. Campbell^ 

 we find that it is one of our most highly-coloured eggs, being 

 " a reddish flesh colour, thickly blotched all over with reddish- 

 brown," but, taking Darwin's view as the correct one (though this, 

 bird is not a highly-coloured one, and so must have sought the 

 hollow for protection against the elements, or against enemies to- 

 its eggs), that the bird first built an open nest, and subsequently- 

 resorted to the hollow bough, I think it is quite possible that 

 the eggs are only now undergoing the process of change (which 

 would necessarily be a slow one), and if we look to the other 

 species of this genus we find this view borne out by the facts. 

 For the eggs show a gradation very marked, from the above 

 highly-coloured species to those of the white-throated Climac- 

 teris leiicoplioea), which are " dull-white, thinly speckled, with 

 fine spots of rich brown and a few large blotches of the same 

 colour," whilst the egg of the nearly-allied Orthonyx spinkaiidus 

 is perfectly white. The same gradation is found with the 

 European genus {Certhia), but none of the eggs of the latter are 

 so highly coloured as the above, nor, indeed, have any of them, 

 more than a few fine spots of brown on the white ground. 



We now proceed to those building domed or concealed nests^ 

 and here I cannot do better than refer to the able paper on 

 the above subject read before the Royal Society of Victoria on 

 the 1 2th May last by our learned president (to which I shall 

 have occasion to refer later), in which he says: — "In many- 

 families it is noteworthy that those kinds of eggs which are quite 

 concealed are white, while those which are exposed are speckled 

 or freckled." 



Illustrations of this rule will be found in the finches of 

 Australia, the domed nest of which almost completely shuts out 

 the light. This Mr. Lucas takes to be the preservation of the 

 ancestral type, but if the above theory be correct, and birds sought 

 the domed nest for protection, it would rather seem to be one 

 of reversion to the original white. The fairy martin (Lagenom- 

 plastes Ariel), whose eggs are mostly of a pure v/hite, but some- 

 times slightly flecked with red, the yellow-rumped acanthiza 

 ( Geohasileiis chysorrhous), with its congener, G. reguloides, and 

 the rock-warbler (Origmes ruhiHcata) are the only members of 

 the family Luscinidce which lay white eggs ; those of the first- 

 named being sometimes slightly speckled — another piece of 

 evidence that the egg was once coloured, and that the colour- 

 ation has died out since the change in the bird's habits ; and 

 their three nests are deeper than that of any other species — the 

 latter being, in addition, built in caves, which are in themselves 

 dark. 



The English long-tailed titmouse is mentioned by Mr. 

 Lucas as possessing similar habits, the nest being deep and th& 



