British Diving Ducks 
Bill and legs, red vermilion; irides, deep red ; length, 25 to 26 inches; wing, 11 
inches; tarsus, 1.9 inch. 
There is no species of duck which commences to assume its eclipse plumage so early in 
the year as the Red-breasted Merganser. In 1883 I killed four adult males on Loch Fyne 
on March 22, and three of these were already in full moult on the neck, the white collar 
having almost disappeared. After the month of March the moult in the full eclipse 
proceeds very slowly, for a specimen I killed on July 6, 1889, on Loch Stennes, 
Orkneys, still retains about a half of its spring plumage, with numerous black feathers in the 
head and neck and the greater part of the mantle, scapulars, and flanks still unmoulted. It 
is not, in fact, until August that the adult male may be said to be in full eclipse. 
I possess a perfect specimen which I killed in Balranald Bay, N. Uist, on August 
20, 1898. I saw the bird some two or three hundred yards away fishing and thought it 
was an adult female, but on its rising to flap its wings I was then certain that it was an 
adult male in full eclipse. Having no shot-gun, but only my old Mannlicher rifle in hand, 
for I was waiting for seals at the time, I did not think there was much chance of being able 
to kill the bird, as it was diving and swimming fast, but seeing that it was the only chance 
I took a long shot at 200 yards and was lucky enough to hit the bird with the bullet in the 
centre of the body, and without in any way injuring the specimen. The description of the 
bird is as follows : 
Head, neck, and upper breast almost exactly similar to adult female, but with only 
a very short area of white on the chin ; mantle and scapulars blackish-brown, edged with 
grey ; wings which have just been renewed as in winter ; rump and lower back a mixture, 
brownish ash-grey feathers like the female, and white vermiculated with black (as in 
spring); flanks and sides of the chest brownish-grey like the female.' There are a few 
slate and brown vermiculated feathers at the sides of the vent. Under parts white, and soft 
parts as in spring, only not so bright. 
Early in September the moult of those parts which will change again commences, and 
it is not completed until the end of November, when the male has again assumed full 
winter dress. 
Immature Female. — In first plumage the young female is similar to the adult female, 
except for the less abundant crest and small area of black round the eye. Tail feathers are 
worn and wing markings less distinct. The scapular and mantle feathers, too, which 
remain unchanged until March, are like nearly all immature female ducks pale and worn 
on their outer edges and generally grey or sandy and unlike the clean rich feathers of 
adults. 
By April it is difficult to distinguish between immature and adult females, except that 
the young never possess the large area of black round the eye nor the black feathers at the 
sides of the chin, and only the throat. The wings are as usual the main character in 
distinguishing age. I do not think these young birds breed nor are they adult until the 
following November. 
Adult Female. — Head and neck reddish-brown and darker on the crown, in some 
cases being almost black on the front of the crown. Chin and throat white and marked 
1 There are only one or two vermiculated feathers on the flanks, and these are mottled with slate and quite different from the 
black vermiculated feathers of the spring plumage. 
