54 British Diving Ducks 
Length, i8 inches ; irides brown ; forepart of the bill-patch pale yellow, becoming reddish- 
orange round and above the nostrils to space in front of the crown. 
Adult Male. — The whole plumage is a deep black with the upper parts glossed 
with purple-blue; the under parts inclined to be brown. The bill has a large pro- 
tuberance at the base of the upper mandible through which there is a line (including 
the nostrils) of rich orange-yellow. The rest of the bill black ; legs olivaceous-brown ; 
irides dark brown. Length, 20 to 21 inches; wing, 9.5 inches ; tarsus, 1.8 inch. 
Like all the Scoters, the local Common Scoter has only a slight eclipse plumage, if it 
may be so called. At the end of July a few dull brown feathers appear on the cheeks, 
throat, and neck. Below the lores and on the throat many of these feathers are of a dirty- 
white colour, and it gives the old male a certain resemblance to a female, and for which they 
have doubtless been mistaken. No author that I can discover mentions having seen this 
eclipse plumage, which is retained to late in the autumn, but I have examined two males 
killed in August in Iceland which exhibit this dress. 
Naumann, dealing with this phase of plumage (Naturgesch. Vdgel Mitteleuropas, 
X. p. 246), says : \ 
" As a differently coloured summer plumage of the adult male has not yet been noticed, I am 
the more sorry to be unable to fill up the gap, for it is more than probable that they have such a 
plumage, because in the late autumn males have been seen which had, amongst the black feathers, still 
a few brown ones here and there, and whitish ones at the throat, and these were specimens which 
could not be considered from all the other signs as young males which had assumed the fully-coloured 
plumage for the first time. The great rarity of quite black males in the autumn, particularly in this 
district where at that time of the year only brown specimens appeared, points to this conclusion. 
Unfortunately, I myself never had the privilege of making observations on this question at the right 
time in the autumn, in the neighbourhood of the sea, where these ducks are common. \Note.—\ too have 
never seen an adult male in the summer plumage. — (R. Blasius.)] " 
The birds described by Naumann might very well have been immature males of 
from 14 to 16 months which had not arrived at adult plumage. 
I have noticed that males are perfectly black all over, with the bill-patch bright 
yellow all through July, but think that a few female-like feathers do appear in front of the 
eye in August. In a note to me, Mr. O. Murray Dixon says : 
" Is it not uncommon to find Common Scoters so far inland in July ? On the 5th of this month 
(191 2) I watched for some time through my glasses three adult males and a female swimming on 
the reservoir here (Loughborough, Leicestershire). The males were entirely black, with long tail 
feathers, and yellow on the bill. This is the first time I have ever seen Scoters here." 
The windpipe of the adult male is somewhat widened in the middle, but has no 
"drum" on the lower larynx, but only a formation similar to that found in most 
female ducks. According to Yarrell, the two bronchial tubes of the male are much 
widened and twice the size of those of the female. 
Immature Female. — Similar to immature male, but somewhat lighter in colour; 
breast inclined to be spotted. In November the sexes are easily separated, and the 
plumage of the adult female commences and is only partly complete by April ; the 
same areas of immature feathers are retained until July as in the young male, when 
a general moult takes place and the wings and tail are shed. The full plumage is 
gained in November at 16^ months. 
