The Body of a Bird pat 
than we now possess of the life-habits and the psychology 
of birds. This is especially true of the great number of 
cases which we can explain only by calling them orna- 
mental and decorative. Hence we find one ornithologist 
Fic. 231.—White-throated Sparrows. The light-coloured bird is in normal plu- 
mage; the dark bird was subjected to moisture-laden air through two moults. 
explaining a certain colour as due to one cause, while 
another scientist gives an entirely different interpretation 
of the same fact. 
From personal observation among the birds of the 
