Miscellaneous. 181 



Birds with black plumage are found in nearly all parts of the globe ; 

 but in certain families, of -which the geographical extension is very 

 wide, the tendency to melanism is scarcely shown except in the 

 southern hemisphere, and^more particularly in the oceanic region 

 which includes New Zealand, Papuasia, Madagascar, and the inter- 

 mediate countries. A remarkable example of this coincidence between 

 the mode of coloration of birds and their distribution on the surface 

 of the globe is furnished by the family of the swans. In the nor- 

 thern hemisphere this family has numerous representatives whose 

 plumage is entirely white ; in the southern hemisphere this is not 

 the case, and a more or less considerable portion becomes intensely 

 black. Thus the Australian swan is almost entirely black ; the cos- 

 coroba, or Cygnus anatoides, which is confined to the Fuegian archi- 

 pelago and neighbouring countries in South America, has some of the 

 wing-feathers black, and it is by this character alone that it differs 

 from the Chinese coscoro^ (C. David it) ; lastly, in the swan of 

 Chili, the head and neck are jet-black, whilst the rest of the body is 

 pure white. These are the only species of swans which live in the 

 southern hemisphere. 



These peculiarities would have but little interest if they were 

 isolated : but this is not the case ; and the examination of the geo- 

 graphical distribution of the colours of the parrots furnishes us with 

 gtill more manifest proofs of the tendency to melanism in the vast 

 oceanic region which includes New Zealand, Papuasia, and the in- 

 termediate lands. 



Black or nearly black parrots are not met with in America, Asia, 

 or Africa (except on the borders of the Mozambique channel), but 

 they are not uncommon in the southern region contained within the 

 limits already mentioned ; and it is there especially that we find the 

 species or local races in which the plumage only pi-esents strongly 

 toned-down tints. Thus, in New Zealand and the adjacent islands, 

 these birds, instead of presenting bright colours, are more or less 

 tinged with black. The Nestors, for example, have dull brown plu- 

 mage ; the larger feathers of the wings and tail, wherever they are 

 exposed to the light, are almost uniformly of a brown tint, resem- 

 bling that produced by a mixture of nine parts of black with one part 

 of orange- red ; on the shoulders, the greater part of the back, the 

 head, and the breast the feathers have a brown border of a still 

 deejier tint ; and in the rest of their surface similar tints are miti- 

 gated by white, so as to become more or less greyish ; and it is almost 

 solely on the tail-coverts and the inner surface of the wings and on 

 the corresponding portion of the flanks, which are not habitually 

 exposed to the light, that an orange-red colour but slightly toned 

 down shows itself here and there. 



The Strigojys or night-parrots of New Zealand also in great part 

 owe their peculiar aspect to another kind of melanism, affecting a 

 greenish ground, and mixed with parts modified by albinism. This 

 jellowish green, which belongs to Nos. 3 and 4 of the chromatic 

 circles, is far from being pure ; it is toned down by about -A or j\ 

 of black, and is interrupted above by spots and irregular bands of 



