46 
The Natural History of British Ducks 
ground, so that the back of the neck and head could be successfully shaken 
and thumped, and during the fight both flopped about on their breasts, and 
did not stand up on their feet, but propelled themselves about as in the water. 
In this contest, curiously enough, the young bird had far the best of it, and 
after it was over the newcomer invariably drove the old bird out of the way, 
and the two never fought again. A fortnight after this contest I again placed 
a freshly caught young cock Wigeon in the pen, and again the old cock gave 
battle with similar results. 
Though the Shoveler may be said to do the same thing, the cock Wigeon 
is one of the very few birds in existence that will pair, and probably breeds 
with the female whilst he himself is in the immature state of plumage. This 
is an important and interesting fact in the life-history of some of the surface- 
feeding ducks, for we know that it is a strict rule amongst birds that they do 
not breed until both sexes have attained the perfectly adult plumage. In 
many cases I believe that various species of birds would breed whilst in an 
immature plumage were it not for the want of fitness in giving battle, and 
their inability to fight successfully with the adult males. Where adult males 
are in sufficient numbers at the breeding grounds immature males, that is, 
young males of the previous year, whose plumage is not quite complete in the 
following breeding season, have no chance to acquire wives, as the older and 
stronger males drive them away ; but when, as occasionally happens, a greater 
number of females come to the breeding grounds unattended by a sufficient 
number of adult males, these immatures get their chance to pair and probably 
breed with females without having to fight for them. 
Certainly I have seen more than once young male Wigeon with the brown- 
grey shoulders of what we understand to be immaturity, paired with the 
female ; but, as I hope presently to show to my readers, this bird is in no 
way really different from what we accept as the perfectly adult bird with pure 
white shoulder, because it is practically the same, as the upper wing at this 
period is not attained afresh, but only changes colour. So the two birds must 
be physically similar though slightly different externally. 
