THE MALLARD. 163 
this tint is due to iron has been proved, but whether it is 
absorbed as a dye from ferruginous waters, as some suppose, or 
secreted from the blood by the feather glands themselves, as 
others hold, seems to be still quite undecided. 
Some females again are considerably less boldly marked than 
the specimen figured. 
I must not omit to notice here the post nuptial plumage that 
the Drakes of this species, in common with those of many 
other species, assume—a sad, dull coloured garb, like that of the 
female. Whether this change is the result of exhausted vigour, 
the outcome of the male’s marital exertions during the breed- 
ing season, or whether the less conspicuousness and consequent 
comparative immunity of the male at the time when the 
young require his care and protection, has led to the pre- 
servation of more young birds of males undergoing this 
change, and has thus converted an accidental variation into 
an hereditary characteristic, it were useless here to enquire ; 
but the fact is one of great interest. Waterton, who watched 
them closely, says: “At the close of the breeding season 
the Drake undergoes a very remarkable change of plumage. 
About the 24th of May, the breast and back of the Drake 
exhibit the first appearance of a change of colour. In a few. 
days after this, the curled feathers above the tail drop out, 
and grey feathers begin to appear amongst the lovely green 
plumage which surrounds the eyes. Every succeeding day 
now brings marks of rapid change. By the 23rd of June 
scarcely one single green feather is to be seen on the head 
ana neck of the bird. By the 6th of July every feather of the 
former brilliant plumage has disappeared, and the male has 
received a garb like that of the female, though of a somewhat 
darker tint. In the early part of August this new plumage 
begins to drop off gradually, and by the 1oth of October the 
Drake will appear again in all his rich magnificence of dress.” 
