Eider-Duck 
males in flocks at the pairing time ; whilst if they attempt to interfere with the females, 
they are driven off by the adult males. As I have myself seen, they go through the full 
" show" of the adult, and are capable of copulation, although their testes are very small at 
this period. Whether the eggs of females paired to these 2-year-old males are fertile or 
not I cannot say. 
Even the young males of lo months go through the full courtship show, and make 
the courting-call similar to the adult, though they do not evince much desire to pair with 
a female. Such, however, is not always the case. On May i, 1912, at Scampston, Mr. St. 
Quintin had on his river-pond four lo-months-old males and one adult female, which was 
most anxious for a mate. All the young males were " showing" and calling, and the old 
female literally hunted the most advanced young male until she got underneath him in the 
water and forced him to pair. Mr. St. Quintin and I witnessed the act twice. The female 
laid eggs, but they were not fertile ; so we must presume that such abnormal pairing is 
unusual and ineffective. 
Female: Down-plumage. — Like that of the male but generally darker on the under- 
parts and the eye-stripe narrower and shorter. 
Juvenile-plumage. — Head and neck brownish-grey with darker centres; eye-stripe 
light grey with dark-brown centres ; mantle, scapulars, back, and rump dark brown with 
light sandy-brown edges ; tail brown and worn at the tips ; upper-wing above and 
including the secondary-coverts blackish-brown edged with rich brown ; primaries nearly 
black ; secondaries blackish-brown with a very narrow edge of pale greyish-brown ; throat 
grey ; breast and belly pale grey-brown crossed with dark greyish-brown bars and 
with sandy grey-brown (the dark bars on the upper-breast are much broader and more 
clearly defined than those on the belly, while the flank-feathers near the rump are also 
more heavily barred). 
Note. — The juvenile female can be distinguished from the juvenile male by its 
smaller eye-stripe and by its paler upper-parts and darker upper-breast. 
First Winter-plumage, — As a rule, the moult is slower in the case of the female, 
which does not commence its first winter-moult until early November. Then the first 
feathers with broad reddish-brown edges appear on the shoulders, lines of a chestnut- 
brown come in on the head, and new black-barred rich brown ones on the upper-breast 
and belly. So the advent of a first semi-adult plumage proceeds slowly until March, 
when the bird has an appearance somewhat similar to the adult female except that the 
wings, tail, and long secondaries have not been renewed, and on close examination 
there are still a large number of the feathers of the juvenile-plumage on the breast 
and belly. The tail is a most variable feature. As a rule it is not renewed until the 
end of the first year, but in very forward birds one or two (generally those in the 
centre) new feathers are gained in spring. By May these lo-months-old females have 
the whole of the breast- and belly-feathers changed and similar to adults. These young 
birds can, however, always be distinguished from adult females by the dark and faded 
long scapulars and secondaries, and by the absence of white on the secondaries and 
secondary-coverts. 
In July these immature females of one year flock together and are again easily 
recognised by their "black" appearance on the water and their faded wings. In many 
