8 A MONOGRAPH OF THE PHEASANTS 



the apparent quick reaction of the plumage pigment to the environmental conditions. 

 At the time I wrote of this in my descriptions" again and again, and I have allowed 

 these interpretations to stand in the monograph text. But I cannot accept this 

 explanation as covering the entire question. The same thing has struck Baker, and he 

 tends to give humidity and other meteorological factors considerable weight. Speaking 

 of the Himalayan birds, of the Lineated and the Silver Kaleege respectively, he says, 

 "Thus we find that the black and very dark birds inhabit areas of dense forest at com- 

 paratively low elevations where there is a heavy rainfall, and which are therefore well 

 provided with rivers, lakes and swamps. Next we see that the grey birds inhabit 

 hills of moderate height covered with mixed forest, bamboos and grasslands, and with 

 a moderate rainfall. Thirdly, we obtain the white birds only in hills and plateaux at 

 a considerable elevation where the grass-covered and open country exceeds in extent 

 the forest, and where the rainfall is slight or even scanty. 



"We thus have it demonstrated that great humidity and heat, with its constant 

 tropical growth of vegetation, induces black in the plumage of the birds of this genus, 

 whereas the coldness of the higher mountains, combined with a drier atmosphere and 

 its consequent higher forests and more open grasslands, induces white. These four 

 factors, temperature, humidity, elevation, and vegetable growth, we shall find, therefore, 

 are the principal ones governing not only the differentiation of the species, but also 

 of the intermediate subspecies." 



Believing thoroughly, as I do, in the darkening effect of humidity, it seems 

 reasonable that this explanation is correct. But I am convinced that it only partly 

 explains the changes in coloration, and that we shall have to await the discovery of 

 unknown factors to be certain. I have kept Himalayan and Silver Kaleege in captivity, 

 under the same extremes of humidity, for many years, have cross-bred and bred them 

 pure, and I have never noticed any change in successive moults or successive generations, 

 either toward melanism or albinism. As I shall mention elsewhere I have shot wild 

 birds from the same flock which differed widely from one another, and in Fokien I 

 have found Silver Kaleege living in numbers in low, coastal, humid country. While 

 these arguments are only partial, yet they make us wary of accepting a wholesale 

 explanation of the Kaleege pigmentation. It is a problem of transcendant interest, 

 which it is hoped may be elaborated before these birds become extinct in their native 

 haunts. 



KEY TO GENNAEUS 



I. Colour dominately black and white (males). 



a Lesser and median wing coverts black and white. 



a' Black and white equal Hneatus. 



b' White dominant over black. 



^" Outer web of outer tail feathers streaked with white nycthemerus. 



b" Outer web of outer tail feathers wholly black whiieheadi. 



b Lesser and median wing coverts glossed with blue. 



d Crest white albocristatus. 



d' Crest black. 



c" Under parts greyish white, 



a'" Rump fringed with white leucomelanos. 



b'" Rump not fringed with white melanonotus. 



d" Under parts black horsfieldi. 



