114 British Diving Ducks 
Adult Male. — Winter plumage: Cheeks, grey in front, passing at the back to a broad 
black patch, which on its lower front becomes light-brown ; the rest of the head and neck 
immediately round the eye, pure white ; above the eye, grey ; back of the neck where it 
joins the mantle, grey, or greyish-white ; mantle, back, tail-coverts, black ; central tail- 
feathers very long and black ; other tail-feathers blackish-grey, with white margins ; wing- 
coverts, primaries, and broad band across the breast, brownish-black ; flanks, white with 
a tinge of grey ; belly and vent, white ; the chin has a small dark-grey patch of feathers just 
below the lower mandible. On first assuming the winter plumage the male generally 
has the whole of the blackish-brown chest-band finely edged with greyish-white, but 
this edging wears off by December. Also, the cheeks and lores of many males come in 
white, only assuming the grey colour in November — a distinct colour change. 
As is the case with many birds, there appear to be two very distinct types amongst 
adult male Long-tailed Ducks — a light and a dark one. The above description applies to 
the common form, namely, the light one. I have, however, seen many examples of a dark 
form which differs considerably from the foregoing. In this case the male has less light 
brown on the side of black cheek and neck patch. It is of a much darker grey on the back 
of the neck above the mantle and the scapulars. In addition there is a smoky greyish black 
edging and spotting to these feathers unnoticed in the light form. Both forms are figured. 
Summer plumage : As early as the last week in March the adult male commences to 
assume its summer plumage, and in some early birds the parts of the plumage which are 
changed, consisting of the head, neck, upper chest, mantle, flanks, and scapulars are com- 
plete as early as the 20th of April, at which date I have killed males in full summer dress. 
Other males do not begin to change until the 8th or loth April, and are not in full plumage 
until the beginning of May, at which date they have generally left our northern coasts. 
Only a few feathers are shed in the spring, from the lower breast and belly, and none from 
the wings, lower back, and tail. The secondaries fade to a much lighter and richer brown 
in April. 
In the summer plumage a small space round the eye is buffish white ; from the ear to 
the bill there is a patch of greyish brown ; the rest of the head, throat, neck, chest, dark 
brown ; mantle black ; space between neck and mantle and scapulars rich red-brown, with 
black centres ; flanks pure grey. The white crown of winter is always the last part to be 
moulted, and sits like a cap on the head above the shorter dark feathers of summer. There 
is often a considerable variation in the colour of the flanks. Generally they are of a rich 
pure grey, but in some instances they remain almost white, as in winter. 
Specimens killed in the early part of July show the summer plumage to be the same as 
that of the spring but much worn and faded, but it is from this date until the middle or end 
of September that the plumage of the male Long-tailed Duck is full of interest, for my 
examinations of specimens during this period have led me to conclude that this duck 
passes into semi-eclipse dress before gaining the winter plumage. 
Many authorities assume that by acquiring a new plumage at the beginning of summer 
the Long-tailed Drake passes directly into its eclipse dress. A close examination, however, 
of a number of males of this species, both in the flesh and in skins, in the months of July, 
August, and September has convinced me that this view is not altogether correct, for what 
may be called a still further change takes place in these months, and may with equal correct- 
