♦ 
BRITISH DIVING DUCKS 
Genus: SOMATERIA 
Until recently it has been the practice of naturalists to regard certain birds inhabiting 
large areas under the title of a single species, and although this is not incorrect, it 
is evident that when a large series is examined, coming from widely separated areas, 
often isolated by intervening localities of unsuitable habitat across which the species 
may or may not emigrate, that there are certain differences apparent both in size and 
details of the plumage. This variation, which we should naturally expect as due to 
environment, temperature, &c., is very well marked in certain species both of birds and 
mammals, and it has caused a large percentage of naturalists who have specialised in 
studying local forms, to adopt a tri-nomial system in dealing with them. Whilst 
most of us deplore the present muddle as regards nomenclature, and may wish to 
follow Dr. Hartert in his desire for strict priority, there are many good naturalists who 
do not agree with the more recent system of naming local races even when well marked, 
and with those I do not agree, although I respect their views. It is quite plain, 
however, to all who deal comprehensively with the subject, that we must have some 
means of recognising these local races, and nothing seems plainer or easier than to 
attach to them some local appellation which will fix the area within which they dwell. 
A case in point is the Eider, whose local races are somewhat variable. 
Formerly we were led by naturalists, who for the most part suffered from a paucity 
of specimens, to consider that all European races of Eiders, and even the American 
ones, belonged to the Swedish race Somateria mollissima, and this held good for a 
time. 
In 1831, Brehm, in his Handbuch der Nahirgesch. aller Vdgel Deutschlands, arranged 
the various races of European Eiders under the titles of Somateria danica, norwegica, 
platyuros, fceroeensis, niegaiiros, islandica, borealis, leisleri, and planifrons, the three 
last named applying to the Greenland race. The race S. megauros is supposed to inhabit 
the islands of the extreme North, perhaps even to be found on the coasts of Germany." 
It was also said to be as small as the Fseroese race and to have 16 tail feathers, 
but Mr. Schioler states that no far-north skins exhibit these characters. Neither can 
the form 5. platyiiros be accepted, as its only distinction is 16 feathers in the tail, 
a character found in various other local races. At present it is difficult to separate the 
Eiders of the British Isles, Denmark, Norway, and those from Finmark eastwards along 
the north coasts of Russia to the peninsula of Yalmal (Kara Sea), which may be described 
as the eastern limit of the species. 
For many years I have made a special study of this duck and its allied races and 
their changes of plumages, and a good part of my time in shooting them and adding 
to my collection of skins, which is now a large one. Moreover, I have never missed 
VOL. II. A 
